9 Critical JT3020 Specs Every Operator Should Know in 2025

The JT3020 stands as a powerhouse in horizontal directional drilling, boasting an impressive 30,000 lbs pullback capacity and 4000 ft-lb of maximum spindle torque.

While its 21,660 lbs operating weight speaks to its robust construction, the machine's true versatility shines through its ability to drill distances up to 650 ft depending on soil conditions. Additionally, equipped with a Cummins QSB4.5 engine delivering 148 hp, this drilling unit maintains optimal performance across diverse job sites.

For operators looking to maximize their drilling efficiency, understanding the critical specifications of the JT3020 can mean the difference between project success and costly setbacks. This comprehensive guide breaks down nine essential specs that every operator should know to fully leverage their equipment's capabilities.

Ditch Witch JT3020 Weight and Dimensions

Precise dimensions and weight specifications define the operational capabilities of any horizontal directional drill. The Ditch Witch JT3020 comes with specific measurements that operators must understand to effectively plan and execute their drilling projects.

Operating Weight Impact on Job Sites

The JT3020 has a standard operating weight of 21,660 lbs (9,825 kg), making it a substantial piece of machinery on any job site. For the All Terrain configuration, the weight increases to 22,200 lbs (10,070 kg), providing enhanced stability during challenging drilling operations. This weight distribution helps maintain balance when applying the machine's 30,000 pounds of pullback force.

The significant operating weight requires proper ground preparation before positioning the drill. Consequently, operators should assess soil compaction and stability to prevent sinking or shifting during operation. Furthermore, the weight impacts transportation logistics, requiring appropriately rated trailers and towing vehicles.

Transport Considerations

When planning transportation, operators must account for the JT3020's specific dimensions. The machine has an overall length of 219.3 inches (5.57 m) in standard configuration, though some sources list the transport length as 221 inches (5.61 m). This slight variation could affect trailer selection and transport permits.

The entry angle ranges from 10° to 16°, which influences loading procedures onto trailers. Notably, the machine features:

• Angle of approach: 19°

• Angle of departure: 18°

These angles are crucial for navigating the drill onto transport vehicles without damaging the undercarriage. Site planners should also consider the weight of additional components such as drill pipe boxes, which can add:

• 4,800 lbs (2,180 kg) for a large box containing 35 pipes

• 3,100 lbs (1,410 kg) for a small box with 20 pipes

Setup Space Requirements

The JT3020's dimensional footprint determines the minimum space needed for safe operation. With a width of approximately 80 inches (2.03 m), operators need to ensure adequate clearance on both sides of the machine for maintenance access and crew movement.

The operational length requires a clear setup zone that accommodates not just the machine's 219.3-inch (5.57 m) length, but also space for pipe handling and spoils management. This typically means planning for a work area that extends at least 15-20 feet beyond the machine's dimensions in both directions.

Height and Width Restrictions

Height specifications vary between operational and transport configurations:

• Operating height: 119 inches (3.02 m)

• Transport height: 94 inches (2.39 m)

This significant difference of 25 inches between operating and transport heights allows the JT3020 to clear most standard highway bridges and overpasses during transport, which typically have minimum clearances of 13-14 feet.

The 80-inch (2.03 m) width means the machine can generally be transported without special wide-load permits in most jurisdictions, though operators should always verify local transportation regulations before moving equipment.

For underground utility contractors working in urban environments, these dimensions often determine which job sites are accessible. Narrow alleyways, limited setbacks between buildings, or low-hanging utility lines might restrict the JT3020's deployment despite its otherwise suitable drilling capabilities.

JT3020 Engine Specifications

At the heart of the JT3020's impressive drilling capabilities lies its powerful Cummins QSB4.5 diesel engine, engineered specifically for demanding horizontal directional drilling applications. This turbocharged powerplant balances robust performance with reliability in challenging underground construction environments.

Cummins QSB4.5 Performance Details

The JT3020 utilizes a 4-cylinder Cummins QSB4.5 diesel engine featuring direct injection technology and liquid cooling systems for optimal heat management. With a displacement of 275 cubic inches (4.5 liters), this engine provides substantial power in a relatively compact package. The engine's precise engineering is evident in its bore and stroke measurements of 4.02 inches (102 mm) and 5.42 inches (138 mm) respectively.

The turbocharged and charge air cooled aspiration system enhances the engine's performance by forcing more air into the combustion chamber, resulting in more efficient fuel burning and increased power output across various operating conditions. This configuration proves particularly valuable when tackling projects in challenging soil conditions or when maintaining consistent drilling speeds is essential.

Fuel Efficiency Metrics

Fuel economy represents a critical consideration for operational costs on drilling projects. The Cummins QSB4.5 in the JT3020 achieves efficiency through its high-pressure common rail fuel system that optimizes fuel injection pressure for improved performance and fuel consumption at every RPM range.

The engine's design prioritizes operational efficiency, with features that include:

• Direct injection technology for optimal fuel atomization

• Turbocharged aspiration that maximizes power without proportional increases in fuel consumption

• Liquid cooling system that maintains optimal operating temperatures

Power Output at Different Conditions

The JT3020's engine delivers a manufacturer's gross power rating of 148 horsepower (110 kW) at 2300 RPM. Moreover, the engine achieves peak gross power of 156 horsepower (116 kW) at 2000 RPM, providing operators with additional power when facing challenging drilling conditions.

This power profile enables the JT3020 to effectively utilize its 30,000 pounds of pullback capacity mentioned in the introduction. The engine's power curve is optimized for directional drilling operations, delivering maximum torque at lower RPM ranges where most drilling work occurs, specifically enhancing performance during backreaming and pullback operations.

Emissions Compliance

In terms of regulatory standards, the JT3020's Cummins QSB4.5 engine complies with EPA Tier 3 and EU Stage IIIa emissions requirements. This compliance level balances environmental responsibility with practical field performance.

The engine achieves these emissions standards through in-cylinder combustion technology rather than requiring extensive external components. Specifically, the engine incorporates:

1. Wastegated turbocharger technology that optimizes air intake across the RPM range

2. Direct injection fuel system that precisely controls fuel delivery

3. Advanced engine management systems that monitor and adjust combustion parameters

For contractors working in environmentally sensitive areas or jurisdictions with strict emissions regulations, this compliance level ensures the JT3020 can be deployed without regulatory concerns in most operating environments.

Pullback and Thrust Capabilities

When evaluating horizontal directional drills, pullback and thrust capabilities stand as critical performance indicators that determine a machine's suitability for various applications. The JT3020's impressive force specifications enable operators to tackle challenging underground installations with confidence.

Maximum Pullback Force (30,000 lbs)

The Ditch Witch JT3020 delivers an impressive maximum pullback force of 30,000 lbs (134 kN), positioning it as a formidable mid-size horizontal directional drill. This substantial pulling capacity enables operators to extract drill stems and attached product pipe through varying soil compositions without excessive strain on the equipment.

In practical applications, this pullback rating provides sufficient force to install utilities across longer bores or when facing unexpected underground obstacles. The 30,000 lbs of pulling power allows the JT3020 to handle installations of product pipe up to 12 inches in diameter, making it suitable for a wide range of utility installation projects including water, gas, and telecommunications lines.

The pullback capacity remains consistent regardless of operating mode, ensuring predictable performance even in challenging soil conditions. Unlike some specifications that vary between standard and specialized configurations, the maximum pullback force maintains its 30,000 lbs rating across all operational modes.

Thrust Capacity for Different Soil Types

In standard operating configuration, the JT3020 generates 24,800 lbs (110 kN) of thrust force[44][45], providing excellent penetration capability for most soil conditions. However, this specification changes significantly when the machine operates in All Terrain mode.

For specialized boring applications in All Terrain mode, the thrust capacity reduces to 16,500 lbs (73 kN)[45]. This deliberate reduction optimizes the machine's performance when utilizing the All Terrain system, which employs specialized drilling techniques for rocky or variable soil conditions.

The difference between standard and All Terrain thrust specifications highlights how the JT3020 adapts to different underground environments:

This dual-mode thrust capability allows operators to select the appropriate configuration based on site-specific soil analysis, maximizing drilling efficiency while minimizing equipment wear.

Carriage Speed Specifications

Beyond raw force measurements, the JT3020's carriage speed specifications reveal important operational capabilities. The machine achieves a maximum carriage thrust travel speed of 120 feet per minute (37 meters per minute)[45], enabling efficient bore creation even on larger projects.

Correspondingly, the carriage pullback travel speed matches this specification at 120 feet per minute (37 meters per minute), maintaining consistent operational tempo during both forward and reverse operations. This balanced performance profile helps operators maintain productivity throughout the entire drilling cycle.

The carriage speed specification becomes particularly relevant when considering the JT3020's ability to bore pilot holes up to 4.5 inches in diameter. The combination of thrust force and carriage speed determines how quickly operators can advance through different soil types, directly impacting project timelines and operational costs.

Together with the impressive pullback capacity, these carriage specifications contribute to the JT3020's reputation as a versatile mid-size directional drill suitable for a wide range of underground construction applications.

Drilling Fluid System Specs

A robust drilling fluid system forms the backbone of any effective horizontal directional drilling operation. The JT3020's fluid system specifications directly impact its drilling efficiency, hole stability, and overall project success across varying soil conditions.

Maximum Pressure and Flow Rates

The Ditch Witch JT3020 delivers impressive fluid handling capabilities with a maximum drilling fluid pressure of 1500 PSI (103 bar). This substantial pressure rating enables operators to effectively transport drilling mud through longer bores while maintaining adequate flow at the cutting face. In essence, this pressure specification ensures proper lubrication and cooling of downhole tools even in challenging ground conditions.

Paired with this high-pressure capability is the JT3020's maximum drilling fluid flow rate of 50 GPM (189 L/min). This flow capacity proves sufficient for:

• Efficient cuttings removal from the borehole

• Proper bit cooling during extended drilling operations

• Effective borehole stabilization in various soil types

• Reduced friction during pullback operations

The combination of 1500 PSI pressure and 50 GPM flow creates an optimal balance for the JT3020's 30,000 lb pullback capacity mentioned earlier. First and foremost, this synergy between systems allows operators to complete bores more efficiently without sacrificing hole quality or stability.

Tank Capacity Considerations

For extended drilling operations, fluid capacity becomes a critical factor. The JT3020 features a 42-gallon (159 L) fluid tank, providing sufficient drilling fluid storage for most standard boring operations without frequent refills. This capacity should be evaluated against:

1. Anticipated bore length and diameter

2. Soil conditions that may require higher fluid consumption

3. Available support equipment for fluid recycling or replenishment

4. Project timeline constraints

On longer or larger diameter bores, operators might need to plan for additional fluid capacity through support equipment. Subsequently, this planning helps minimize downtime and maintains consistent drilling progress throughout the project.

Fluid Pump Specifications

The JT3020's fluid pump system works harmoniously with its powerful Cummins engine to deliver consistent performance. The pump system achieves the previously mentioned 1500 PSI maximum pressure [59] while maintaining efficiency across various operating conditions.

Key pump performance attributes include:

• Consistent pressure maintenance during rotation and pullback operations

• Reliable flow rates across different drilling phases

• Compatibility with various drilling fluid mixtures including bentonite-based and polymer systems

The hydraulic reservoir, though not directly part of the drilling fluid system, complements system operations with its 27-gallon (102 L) capacity. This reservoir ensures proper hydraulic power is available to drive the fluid pump system consistently.

For operators planning extensive usage in challenging soil conditions, the fluid system specifications should be carefully matched with project requirements. In fact, the JT3020's fluid capabilities represent one of its most significant advantages for mid-sized drilling projects, providing sufficient power for larger bores while maintaining operational efficiency.

When evaluating fluid system performance across different drilling platforms, the JT3020's specifications position it as a versatile performer capable of handling a wide range of underground utility installations where both pressure and volume requirements fall within its operational parameters.

Drill Rod Specifications for the JT3020

Selecting appropriate drill rods for the JT3020 directly affects boring success, with each rod specification playing a vital role in project outcomes. The right rod choice impacts everything from drilling accuracy to equipment longevity.

Compatible Drill Rod Types

The JT3020 primarily utilizes 2.11-4 thread pattern drill rods specially designed for its operational requirements. These rods measure 3000mm (9.84ft) in length with a pipe outer diameter of 60mm (2.38 inches) and a tool joint outer diameter of 76.2mm (3 inches).

For optimal compatibility, operators should select rods specifically manufactured for the JT2720M1/JT3020M1 models. These rods feature precision-fabricated components, including:

• 4137H extra wear-resistant bar stock material

• Heat-treated tool joints meeting API S135 specifications

• 4100 alloy series high chromemoly seamless tube bodies

The inertia welding process used in manufacturing these rods ensures structural integrity under the combined stresses of pulling, thrusting, and rotational forces.

Bend Radius Limitations

Bend radius specifications determine the JT3020's ability to navigate underground obstacles. The minimum bend radius for JT3020 drill rods is 42.9m, accordingly limiting the machine's turning capabilities in confined spaces.

In practical terms, these rods allow a maximum bending ratio of 4.4° per rod, which operators must factor into bore planning to prevent excessive stress on equipment. This bending capacity translates to a maximum built ratio of 7.7% slope per rod, essential knowledge for operators designing bore paths around underground infrastructure.

Rod Weight and Handling

Individual JT3020 drill rods weigh approximately 90-100 lbs (41-45 kg) each, requiring appropriate handling equipment and procedures. This substantial weight impacts both transportation logistics and on-site handling requirements.

When considering full rod packages, weight calculations become even more significant:

• Large box with 48 pipes: 5,500 lbs (2,500 kg)

• Small box with 24 pipes: 3,200 lbs (1,410 kg)

Proper lifting equipment and secure storage solutions are therefore essential for safe and efficient operations, especially considering that drill rod replacement represents a substantial operational expense over the machine's lifetime.

Torque Specifications

The JT3020's drill rods feature impressive torque capabilities that complement the machine's powerful drilling system. With a yield torque rating of 6,823 N-m, these rods withstand significant rotational forces during drilling operations.

Make-up torque specifications of 4,094 N-m ensure proper connection between rods without overtightening, which could damage threads or reduce operational lifespan. Furthermore, the tensile strength of 1,106,654 N provides sufficient capacity to handle the machine's 30,000 lbs pullback force without structural failure.

The rod specifications align perfectly with the JT3020's maximum spindle torque capabilities, creating a balanced system that maximizes drilling efficiency while maintaining operational reliability across diverse underground conditions.

Operational Controls and Electronics

Effective operation of the JT3020 hinges primarily on the operator's mastery of its control systems, which serve as the critical interface between human decision-making and the machine's powerful capabilities. Understanding these systems thoroughly enables operators to maximize productivity while minimizing wear on components.

Control Panel Features

The JT3020's control panel layout prioritizes operational efficiency through intuitive design. According to manufacturer documentation, proper operation procedures are outlined in the dedicated beige Operation Overview pages of the official manual. These essential pages provide step-by-step guidance for mastering the machine's control interface.

The control system architecture follows Ditch Witch's established design philosophy, organizing drilling functions into logical groupings based on operational sequence. Operators familiar with other Ditch Witch equipment will notice consistency across the product line, reducing learning curves when transitioning between machines.

For optimal performance, operators must follow the manufacturer's specified operating procedures without deviation. First, this ensures safety during operation. Secondly, it protects the significant investment the JT3020 represents. Finally, it maximizes productivity across diverse drilling conditions.

Diagnostic Capabilities

The JT3020's diagnostic systems provide crucial performance feedback, allowing operators to monitor machine health continuously. As indicated in the operation documentation, these systems enable real-time assessment of various operational parameters.

Routine diagnostic procedures outlined in the operation manual serve as essential preventative maintenance tools, helping identify potential issues before they escalate into costly repairs or downtime. Knowledge of these diagnostic capabilities proves particularly valuable for projects in remote locations where technical support may not be immediately available.

Remote Operation Options

While the standard JT3020 configuration operates through its integrated control panel, some operations benefit from remote control capabilities in specific applications. The machine's core functions must be managed according to procedures outlined in the comprehensive operation manual.

Ultimately, regardless of control system configuration, operators should adhere to The Charles Machine Works' operational guidelines to maintain warranty coverage and machine performance. As noted in warranty documentation, proper operation directly impacts both short-term productivity and long-term equipment durability.

For operations involving the JT3020, the directional-drilling-store.com provides access to operational resources that complement manufacturer documentation, further supporting operational excellence across the full range of horizontal directional drilling applications.

Tracking System and Mobility Specs

The mobility features of the JT3020 play a crucial role in jobsite efficiency, with specialized tracking systems that enhance both transportation capabilities and operational stability in challenging environments.

Ground Drive Speed

The JT3020 delivers consistent ground travel capabilities with a forward speed of 2.4 mph (3.9 km/h). In reverse operations, the machine maintains nearly equivalent momentum at 2.25 mph (3.6 km/h). These travel speeds strike an effective balance between jobsite maneuverability and controlled positioning for precise drill setup.

In comparison to similar class machines like the JT20, which offers 3.2 mph (5.2 km/h), the JT3020 prioritizes stability over raw speed. This design choice becomes particularly valuable when navigating through confined residential areas or positioning on uneven terrain where controlled movement proves more important than rapid transit.

Tracking System Durability

The JT3020 utilizes industrial-strength rubber tracks specifically formulated with a high concentration of natural rubber to resist cracking under demanding conditions. These tracks adhere to OEM specifications while incorporating specialized bonding adhesives that enhance longevity in rugged environments.

Different tread patterns accommodate various drilling environments:

• H/C pattern treads excel in mud, snow, dirt, rocks, and clay

• Zig-zag patterns provide superior traction on snow, mud, and clay surfaces

• Straight bar treads optimize performance in wet and muddy conditions

• Multi-bar designs handle loose terrain while maintaining effectiveness on hard surfaces

Terrain Handling Capabilities

First and foremost, the JT3020 All Terrain model features patented dual-drive pipe technology that enables simultaneous drilling and steering operations. This innovative system allows effective boring up to 650 feet in various soil types, including solid rock.

Alongside this capability, the machine incorporates an exclusive double-pivot drill frame permitting steep entry angles without lifting tracks off the ground. As a result, operators maintain maximum stability during drilling operations. The hydraulic heavy-duty anchor system secures the machine firmly on most surfaces, enhancing operational stability across diverse terrain conditions.

Interestingly, the tracking system works in harmony with the machine's electronic beacon technology. The relatively short beacon length enables precise positioning in a steel housing just behind the drilling head, providing real-time steering corrections during boring operations.

Maintenance Intervals Based on Specs

Proper maintenance remains vital for maximizing the JT3020's operational lifespan and ensuring peak performance across drilling projects. Establishing a systematic maintenance schedule based on the manufacturer's specifications helps prevent costly downtime and extends equipment longevity.

Engine Service Requirements

The JT3020's Cummins QSB4.5 diesel engine demands consistent attention to maintain its 148 hp (110 kW) output capacity. Regular service intervals typically include:

• Oil and filter changes

• Fuel filter replacement

• Air filter inspection and replacement

• Cooling system maintenance

First and foremost, operators should follow the detailed service intervals outlined in the equipment manuals available through the Ditch Witch support portal. These manuals provide comprehensive maintenance schedules tailored specifically to the JT3020's operational requirements under various working conditions.

Hydraulic System Maintenance

Maintaining the JT3020's hydraulic system proves essential for preserving the machine's 30,000 lbs pullback capacity. The hydraulic reservoir requires regular monitoring to maintain its 27-gallon (102 L) capacity.

Primarily, if the hydraulic system must be opened for repair, installing a new filter (p/n 153-791) for the first 50 hours afterward is mandatory. This precaution prevents potential contamination from circulating through the system after service.

Routine hydraulic maintenance typically includes checking:

• Fluid levels and condition

• Filter cleanliness

• Connection integrity

• System pressure consistency

Wear Part Replacement Schedules

The saver sub represents a critical wear item that connects to every joint of pipe during operations. Essentially, regular inspection of this component is necessary, with replacement required when wear becomes evident.

Replacement parts should be sourced exclusively through authorized Ditch Witch dealers to maintain equipment warranty protection. The manufacturer specifies that using non-ProTech replacement parts may reduce equipment productivity and potentially void warranty coverage.

For comprehensive maintenance information, operators should consult the official Ditch Witch JT3020 manual. Additionally, maintenance resources can be found through specialized suppliers like directional-drilling-store.com which offers compatible maintenance components.

Ultimately, establishing and following a rigorous maintenance schedule based on the manufacturer's specifications ensures the JT3020 delivers consistent performance throughout its operational lifespan.

Cost of Operation Considerations

Understanding the financial implications of operating the JT3020 helps contractors calculate project costs accurately and optimize their equipment investment. Beyond the initial purchase price, several ongoing expenses directly impact the machine's total cost of ownership.

Fuel Consumption Rates

The JT3020 operates exclusively on diesel fuel, specifically designed to run on high-quality fuel meeting ASTM D975 No. standards. With a substantial 42-gallon (159 L) fuel tank capacity, the machine can sustain extended drilling operations without frequent refueling interruptions.

Fuel efficiency varies based on operational conditions, with higher consumption during maximum pullback operations versus idle or light boring activities. Primarily, the Cummins QSB Turbo Diesel engine balances power delivery with reasonable fuel economy for its class.

For cold weather operations, operators should consult the engine manual for specific fuel recommendations, as improper fuel selection can increase consumption rates and potentially damage sensitive engine components. Indeed, using the manufacturer-recommended #2 diesel fuel helps maintain optimal performance while minimizing unnecessary fuel expenses.

Wear Part Expenses

Track replacement represents one of the most significant recurring expenses for JT3020 operators. High-quality replacement tracks feature helically wound continuous steel cords coated for rust protection, designed specifically for reliable service in demanding conditions.

When budgeting for operational costs, contractors should account for:

• Non-recycled rubber tracks that deliver superior durability

• Cut-resistant edges that extend operational lifespan

• Premium heavy-duty guide systems that minimize premature wear

Straightaway investing in quality replacement parts from authorized dealers typically proves more economical than purchasing lower-cost alternatives that may require more frequent replacement.

Resale Value Factors

The JT3020 generally maintains strong resale value compared to similar equipment, assuming proper maintenance documentation exists. Multiple factors influence this value, including:

Machine age and total operational hours Detailed maintenance records showing adherence to manufacturer schedules Overall condition of major components, particularly the engine and hydraulic systems Completeness of original equipment, including pipe packages

Firstly, financing options are available for qualified buyers, making both new and used units accessible to contractors of various sizes. Additionally, the machine's proven reliability in a wide range of applications creates consistent demand in the secondary market, supporting stronger residual values compared to less versatile equipment.

Comparison Table

Conclusion

Understanding the JT3020's specifications proves essential for operators seeking optimal performance in horizontal directional drilling projects. The machine's 30,000 lbs pullback capacity, paired with its Cummins QSB4.5 engine delivering 148 hp, positions it as a capable mid-size drilling unit for diverse applications.

The comprehensive specifications, ranging from precise dimensional requirements to detailed maintenance schedules, enable contractors to make informed decisions about equipment deployment and project planning. Operators who master these specifications can effectively utilize the JT3020's capabilities across various soil conditions while maintaining optimal operational efficiency.

The machine's balanced design, evidenced through its 21,660 lbs operating weight and 50 GPM maximum fluid flow rate, demonstrates thoughtful engineering focused on practical jobsite requirements. These specifications, combined with the unit's versatile tracking system and robust drill rod compatibility, establish the JT3020 as a reliable choice for underground construction projects requiring both power and precision.

Ultimately, successful operation depends on thorough knowledge of these nine critical specifications, proper maintenance adherence, and careful consideration of operational costs. Contractors who apply this technical understanding while following manufacturer guidelines position themselves to maximize their equipment investment and achieve consistent project success.

FAQs

Q1. What is the maximum pullback force of the Ditch Witch JT3020? The Ditch Witch JT3020 has a maximum pullback force of 30,000 lbs (134 kN), making it suitable for a wide range of underground utility installations.

Q2. What are the key dimensions of the JT3020? The JT3020 has a length of 219.3 inches (5.57 m), width of 80 inches (2.03 m), and an operating height of 119 inches (3.02 m). Its transport height is 94 inches (2.39 m).

Q3. What engine powers the JT3020 and what is its horsepower? The JT3020 is powered by a Cummins QSB4.5 diesel engine that delivers 148 horsepower (110 kW) at 2300 RPM, with a peak power of 156 horsepower (116 kW) at 2000 RPM.

Q4. What are the drilling fluid system specifications for the JT3020? The JT3020 has a maximum drilling fluid pressure of 1500 PSI (103 bar) and a maximum flow rate of 50 GPM (189 L/min). It features a 42-gallon (159 L) fluid tank capacity.

Q5. What is the ground drive speed of the JT3020? The JT3020 has a forward ground drive speed of 2.4 mph (3.9 km/h) and a reverse speed of 2.25 mph (3.6 km/h), providing efficient jobsite mobility.