Heavy Truck Brake Fade on Mountain Grades and Using a Runaway Truck Ramp¶

Descending a steep mountain grade (5 to 10 percent slope) in a loaded commercial tractor-trailer (36,287 kilograms / 80,000 pounds Gross Vehicle Weight), heavy dump truck, Class A diesel pusher motorhome, or pickup towing a heavy fifth-wheel trailer requires dissipating millions of joules of gravitational potential energy every minute. When a driver selects too high a transmission gear at the summit or drags the service brakes continuously down a long mountain pass, cast-iron brake drums and rotors heat past 425 to 600 degrees Celsius (800 to 1,100 degrees Fahrenheit). At that temperature threshold, two catastrophic failures occur simultaneously: first, organic/semi-metallic brake lining resins vaporize into a lubricating gas boundary layer while the metal brake drums thermally expand away from the S-cam brake shoes (thermal fade and mechanical drum run-out), reducing stopping power to near zero even at maximum 690 to 825 kPa (100 to 120 psi) air application pressure; second, drivers who repeatedly fan or pump an air brake pedal bleed compressed air out of the primary and secondary reservoirs faster than the engine air compressor can replenish it, risking sudden Spring Brake Pop-Out (45 to 20 psi emergency lockup) or wheel-end grease fires.

Once service brakes fade on a 6 percent downgrade, gravity accelerates a heavy truck from 80 km/h (50 mph) to over 145 km/h (90 mph) in less than 45 seconds. Knowing how to descend grades using the Proper Gear + Engine Retarder + Snub Braking Method, recognizing the early smell and mirror signs of brake smoke before total fade occurs, avoiding fatal neutral gear jumps or trailer-hand-valve jackknifes, and steering dead-center into a gravel arrestor bed Runaway Truck Ramp saves your life and the lives of every motorist on the mountain.

Do this now¶

1. IF YOU ARE CURRENTLY LOSING BRAKES ON A MOUNTAIN DOWNGRADE: Turn ON the Engine Brake (Jake Brake) / Transmission Retarder to MAXIMUM HIGH immediately, and DO NOT shift into Neutral. Flip the dashboard engine compression brake or hydraulic/electric retarder switch to its highest stage (Stage 3 / MAX). NEVER depress the clutch or push the gear lever out of gear to try to downshift a non-synchronized heavy truck transmission once the truck is already speeding out of control: as soon as you pull the shifter into Neutral on a steep grade, road speed spikes in 1 second, making it physically impossible to match engine RPM to road speed, leaving you trapped in "Georgia Overdrive" (freewheeling in Neutral with zero engine braking). Keep the truck in whatever gear it is currently engaged in.
2. ALERT ALL OTHER DRIVERS AND LOOK FOR THE NEXT RUNAWAY TRUCK RAMP SIGN: Turn on 4-way hazard flashers, turn on high-beam headlights, and sound the air horn continuously. Warn slower passenger cars ahead of you to clear the right lane immediately. Scan the right shoulder (or occasionally the center/left median on divided mountain interstates) for highway signs reading RUNAWAY TRUCK RAMP : 1 MILE / TRUCK ESCAPE RAMP and prepare to take the first ramp you reach (see brake failure while driving for passenger car protocols).
3. DO NOT FAN OR PUMP AIR BRAKES, AND DO NOT YANK THE TRAILER HAND VALVE ("JOHNSON BAR") ON CURVES: Unlike hydraulic car brakes, pumping an air brake pedal dumps huge volumes of compressed air out the exhaust port on every release without giving hot drums time to cool, rapidly draining your air tanks toward total system loss. Even worse, pulling the steering-column Trailer Hand Valve (Trolley Valve / Johnson Bar) hard while entering a mountain curve locks the trailer axles and causes an instant, uncontrollable trailer swing jackknife.
4. COMMIT TO THE RUNAWAY TRUCK RAMP EARLY: Line up the tractor and trailer dead-center, hold the steering wheel firmly at 9 and 3 o'clock (thumbs OUTSIDE the spokes), and enter straight. Never pass up a runaway truck ramp hoping your smoking brakes will cool down or fearing a towing bill; mountain grades almost always get steeper and curvier near the bottom. Steer straight into the center of the pea-gravel arrestor bed (do not straddle the concrete wall or enter at an angle, which causes the trailer to jackknife or roll over). Brace your head and back against the seat as the deep river gravel decelerates the rig at 0.4 to 0.8 G, sinking the axles up to the frame rails.
5. IF NO RUNAWAY RAMP EXISTS AND A DEADLY CURVE OR TRAFFIC STOP IS AHEAD: Scrub speed along an uphill earthen embankment or guardrail BEFORE the truck hits 130+ km/h (80+ mph). If you are on a two-lane mountain road without escape ramps, act early while you are still traveling 65 to 80 km/h (40 to 50 mph) rather than waiting until 145 km/h (90 mph). Steer onto a wide gravel shoulder, ditch line, or brush the right side of the rig at a shallow 5-to-10-degree angle against an upward-sloping dirt/rock cutbank (never the cliff drop-off side) to friction-scrub speed before the fatal hairpin turn.
6. ONCE STOPPED IN THE GRAVEL BED OR ON THE SHOULDER: Expect an immediate wheel-end tire/grease fire once airflow stops. When a runaway truck with 600°C (1,100°F) glowing brake drums comes to a stop, the cooling 100 km/h windstream vanishes and radiant heat conducts inward into the wheel hub oil/grease seal and tire bead, igniting a wheel-end fire within 2 to 10 minutes. Call local emergency numbers (911 in the US/Canada, 112 in Europe, 999 in the UK), grab your cab ABC dry-chemical fire extinguisher, and stand upwind away from overheated tires (which can explode from tire pyrolysis at 1,000+ kPa / 150+ psi).

flowchart TD
    A["Heavy Truck / Towed Rig Experiencing Brake Fade on Mountain Downgrade"] --> B["IMMEDIATE CAB ACTIONS:<br/>1. Set Engine Brake (Jake Brake) / Retarder to MAX Stage 3<br/>2. DO NOT shift out of gear or press clutch (Avoid Neutral trap)<br/>3. Turn ON 4-Way Hazards + High Beams + Continuous Air Horn"]
    B --> C{"Is a Runaway Truck Ramp / Gravel Arrestor Bed Ahead on This Grade?"}
    C -->|"YES: Escape Ramp Sign Posted"| D["COMMIT TO THE FIRST RAMP:<br/>Align tractor & trailer 100% straight before entry; grip wheel at 9 & 3 (thumbs outside spokes); enter center of pea-gravel bed"]
    C -->|"NO: No Escape Ramp & Speed Climbing Toward Hairpin Curve / Traffic"| E["ACT EARLY BEFORE SPEED EXCEEDS 80 KM/H (50 MPH):<br/>Hold firm steady air pressure (do NOT fan pedal); steer onto uphill gravel ditch or scrub right side shallowly against uphill dirt embankment"]
    D --> F["POST-STOP FIRE & ROLLBACK PROTOCOL:<br/>1. Pull Yellow Tractor & Red Trailer Parking Valves (if drums are not glowing red-hot, or chock wheels in gravel)<br/>2. Exit cab with ABC Fire Extinguisher; call 911 / 112 / 999"]
    E --> F
    F --> G{"Are brake drums smoking heavily or glowing dull cherry red?"}
    G -->|"YES: Extreme Thermal Runaway at Wheel Ends"| H["STAND CLEAR OF TIRES (Pyrolysis Explosion Hazard):<br/>Use dry-chemical extinguisher from 3-5 m (10-15 ft) at an angle from front/rear (NEVER stand directly facing the wheel rim); NEVER pour cold water on red-hot cast-iron drums"]
    G -->|"NO: Moderate smoke only"| I["Keep engine idling at 1,200 RPM for turbo cooldown; wait 45-60 min for drums to cool & certified mechanic to inspect S-cam pushrod stroke before moving"]

Physics of Heavy Truck Brake Failure: The 4 Mechanisms That Destroy Stopping Power¶

Understanding the difference between thermal lining fade, mechanical drum expansion ("running out of stroke"), pneumatic air depletion, and hydraulic trailer surge/electric fade explains why pressing harder on the treadle valve stops working on a mountain pass.

Phase 1: Prevention at the Summit & Executing the Proper "Snub Braking" Technique¶

Every fatal mountain runaway starts at the top of the grade, before the road even tilts downward. Both the U.S. Federal Motor Carrier Safety Administration (FMCSA Commercial Driver's License Manual) and European professional HGV guidelines teach the modern Snub Braking + Engine Retarder Method (note: the old 1970s myth of holding continuous light 10-psi steady pressure all the way down a mountain has been proven by NHTSA testing to overheat brakes because the drums never leave contact with the shoes).

Step 1: The Summit Brake-Check Area Protocol (Before Starting Down the Grade)¶

Whenever you approach a yellow highway sign indicating a 5% to 9% Downgrade Ahead, pull into the mandatory Truck Brake-Check Area at the summit: 1. Verify Air System Governor Cut-In / Cut-Out Pressure (85 to 100 psi cut-in, 120 to 135 psi cut-out): Confirm both Primary and Secondary air gauges are at full cut-out pressure (825 to 930 kPa / 120 to 135 psi) with zero audible air leaks. 2. Walk Around and Check Wheel Hubs and Slack Adjusters: Inspect every tractor and trailer wheel end. If you smell hot grease or see one cold brake drum while others are warm, that brake is out of adjustment and will force the remaining brakes to carry an overloaded thermal burden on the descent. 3. Select Your Descent Gear BEFORE Crossing the Crest (Not "Use the Same Gear You Climbed Up In"): Modern high-torque turbocharged diesel engines (500 to 600 horsepower, 2,500 Nm / 1,850 lb-ft torque) and aerodynamic tractors can easily pull a 36,287 kg (80,000 lb) load UP a 6 percent grade at 70 km/h (45 mph) in 9^th or 10^th gear. Going DOWN that same 6 percent grade with low rolling resistance requires a much lower gear (typically 6^th or 7^th, at 35 to 55 km/h / 20 to 35 mph) so the engine compression brake (Jake Brake) can hold the weight without dragging the service brakes. Select your low gear and set your Safe Target Speed while still on flat ground at the summit.

Step 2: How to Execute the Official FMCSA "Snub Braking" Cycle on the Downgrade¶

Once descending the mountain grade with your Engine Brake (Jake Brake) switched ON to Stage 2 or 3 (High) and your transmission locked in a low gear that keeps engine RPM in its peak retarding band (1,700 to 2,100 RPM): 1. Establish your Safe Target Speed (for example, 55 km/h / 35 mph on a steep 6% to 7% grade, or lower as posted for your gross weight) and allow the truck to drift up to that speed held primarily by the engine compression brake. 2. Apply a firm, decisive 3-to-4-second "Snub" of the foot brake pedal (15 to 25 psi application pressure) to drop your road speed by 8 km/h (5 mph) down to 48 km/h (30 mph). 3. Release the foot brake pedal COMPLETELY so the brake shoes pull away from the drums, allowing cold mountain air to circulate through the wheel ends while the engine brake holds the rig for the next 15 to 30 seconds as speed slowly creeps back from 30 mph to 35 mph. 4. The Critical Warning Sign That Your Gear Is Too High: If the interval between your 5-mph brake snubs shrinks to less than 10 to 15 seconds, your transmission gear is too high for the grade and your brakes are accumulating heat faster than they can cool. Stop safely in a wide turnout immediately while your brakes are still functional, shift down 1 or 2 full gears from a dead stop, and resume the descent at a slower target speed.

Phase 2: How to Use a Runaway Truck Ramp (Escape Ramp / Arrestor Bed) Without Rolling Over¶

When service brakes fade completely on a mountain pass and road speed climbs past 90 to 130 km/h (55 to 80 mph), a Runaway Truck Ramp is an engineered lifesaving cushion designed to stop a 36,287 kg (80,000 lb) tractor-trailer without injuring the driver.

1. The 3 Types of Runaway Truck Ramps and How They Work¶

Highway departments build three types of escape ramps: 1. Gravity + Pea-Gravel Arrestor Bed (Most Common and Safest): A long lane branching off the right shoulder (150 to 400 meters / 500 to 1,300 feet long) filled 45 to 100 centimeters (18 to 40 inches) deep with washed, rounded, uniform-size pea gravel (river stone). Rounded pea gravel does not compact or freeze solid in winter and acts like a fluid pit of ball bearings: when the truck tires hit the gravel at 130 km/h (80 mph), the wheels sink up to the axles and push a wave of gravel ahead of the tires, generating a smooth drag deceleration of 0.4 to 0.8 G. 2. Flat Sand / Gravel Arrestor Bed: Used where steep canyon walls prevent building an uphill ramp; relies 100 percent on deep gravel drag to stop the truck on a level apron. 3. Mechanical Cable-Net / Drag-Net Escape Ramp: Uses stainless-steel energy-absorbing cable nets connected to hydraulic friction reels stretched across a paved lane to catch the tractor like an aircraft carrier tailhook.

2. Why Drivers Hesitate Instead of Taking the Ramp¶

Forensic investigations of fatal runaway truck crashes by the National Transportation Safety Board (NTSB) repeatedly find that drivers passed clearly marked Runaway Truck Ramps before crashing at the bottom of the mountain due to three myths: - Myth 1 ("The ramp will flip the truck over"): Pea-gravel arrestor beds are engineered to absorb impacts at 130 to 160 km/h (80 to 100 mph). As long as you enter straight and centered, the sinking gravel holds the tires upright in deep trenches, preventing a rollover. - Myth 2 ("I will get fined $10,000 by the DOT"): Highway departments do NOT issue a traffic citation simply for using an escape ramp (though a post-incident inspection is performed, and heavy-wrecker winching from deep gravel costs the carrier $2,500 to $8,000). Compare a wrecker bill to a fatal crash at the bottom of the canyon. - Myth 3 ("Maybe the hill levels out around the next bend"): Highway engineers only build a Runaway Truck Ramp directly ahead of a section where the grade stays lethal or ends in a low-speed hairpin curve, tunnel, or intersection. If you see a Runaway Truck Ramp and your brakes are smoking, TAKE IT.

3. Step-by-Step Steering & Entry Technique Into the Arrestor Bed¶

1. Line Up Early on the Paved Apron: Do not swerve sharply into the ramp at the last split-second; a violent steering jerk at 130 km/h (80 mph) swings the trailer sideways before the tires touch the gravel, causing the rig to enter broadside and roll over.
2. Aim Dead-Center (Never Ride the Paved Service Strip on the Side): Many gravel arrestor beds have a narrow 3-meter (10-foot) paved concrete service lane running alongside the gravel bed for tow trucks. Never put your left wheels on the pavement and your right wheels in the deep gravel: that split-traction differential (0.8 G drag on the right tires vs. 0.0 G on the left tires) will yank the steering wheel to the right and jackknife the trailer. Put all 18 wheels squarely in the middle of the gravel.
3. Grip the Steering Wheel at 9 and 3 o'clock with Thumbs OUTSIDE the Rim: When the front steer tires hit 60 centimeters (24 inches) of pea gravel at highway speed, the wheel can kick violently left and right. Hooking your thumbs inside the spokes can fracture both thumbs; hold the outer rim firmly with your thumbs resting on the front face of the rim.
4. Brace Your Head Against the Headrest: The truck will pitch nose-down as the front axle sinks, throwing a wave of gravel and dust over the hood and windshield for 4 to 8 seconds until the rig stops completely, with the deep gravel automatically chocking all 18 wheels in place.

Phase 3: Preventing a Jackknife When Brakes Are Fading or Wet/Icy¶

A tractor-trailer jackknife occurs when the tractor's drive axles or the trailer's tandem axles lock up and lose lateral traction, causing the articulated fifth-wheel hinge to fold like a pocketknife until the trailer slams into the cab or sweeps across all lanes of traffic.

1. The 3 Types of Articulated Jackknife and What Causes Each¶

1. Tractor Drive-Axle Jackknife (Fastest and Deadliest, 1.5 to 3 Seconds):
2. Cause: The tractor's rear drive wheels lock up or retard harder than the trailer wheels (either from locking the drive brakes on wet/icy pavement or running the Jake Brake on High Stage 3 on a slick, icy, or lightly loaded mountain curve), while the heavy unbraked trailer keeps pushing forward against the fifth-wheel kingpin.
3. Result: The rear of the tractor kicks sideways in under 2 seconds. Once the angle between the tractor and trailer exceeds 15 degrees, steering counter-correction can no longer recover the rig, and the cab spins 180 degrees backward into the front corner of its own trailer.
4. Trailer Swing Jackknife:
5. Cause: The trailer tandem wheels lock up (often because an uninformed driver yanks the Trailer Hand Valve / Johnson Bar on a downhill curve thinking it will "stretch the rig out," or because an empty trailer bounces and locks its wheels).
6. Result: Because a locked sliding tire has zero directional stability, centrifugal force swings the back of the trailer out wide across oncoming lanes like a pendulum.
7. Steering-Axle Push (Understeer Skid):
8. Cause: Front steer tires lock up on wet pavement or gravel, causing the truck to plow straight ahead toward the cliff edge regardless of how far the driver turns the steering wheel.

2. How to Use the Engine Brake (Jake Brake) Safely Without Jackknifing¶

• On Dry Pavement with a Loaded Trailer: Keep the Engine Brake on Stage 3 (High / All 6 Cylinders) for maximum retarding power.
• On Wet, Snow-Covered, or Icy Mountain Grades (or When Pulling an Empty / Bobtail Tractor): High engine compression braking applies retarding torque only to the tractor's drive axles, with zero braking on the steer axle or trailer axles. On black ice or wet curves, Stage 3 Jake Brake can break the drive tires loose and cause an instant tractor jackknife. On slick surfaces, step the Engine Brake down to Stage 1 (Low, 2 cylinders) or OFF, or rely on coordinated ABS-modulated foot braking at a much slower crawl speed.

Phase 4: Post-Stop Wheel-End Fire & Tire Pyrolysis Explosion Defense¶

Stopping a runaway truck is only half the emergency. Dozens of trucks that successfully stop in a runaway ramp or on a highway shoulder burn to the ground 5 to 15 minutes later because of conductive heat soak.

1. Why Brakes Catch Fire AFTER You Stop: While the truck is moving at 100 km/h (60 mph), fast air rushing past the wheels blows flames out and carries away surface heat while the inner cast-iron drum core sits at 600°C (1,100°F). The moment the truck stops, airflow drops to zero. Stored heat inside the iron drum conducts inward into the wheel hub oil bath (80W-90 gear oil or wheel bearing grease), the rubber brake chamber diaphragm, and the steel tire bead, igniting a grease and rubber fire.
2. Do NOT Set the Parking Brakes if Drums Are Glowing Red-Hot (If the Truck Is Chocked in Gravel): If you are buried axle-deep inside a pea-gravel arrestor bed where the truck cannot roll, leaving the spring parking brakes applied clamps the overheated brake linings against the glowing 600°C iron drum, trapping heat, igniting the linings, and cracking the cast-iron drum as it cools.
3. NEVER Pour Cold Water onto Glowing Red-Hot Cast-Iron Brake Drums: Dousing a cherry-red cast-iron brake drum or rotor with cold water causes instant thermal shock, shattering the cast iron. Instead, use your Cab ABC Dry-Chemical Fire Extinguisher deployed in short bursts at the base of any grease/seal flames, or smother smoking wheel ends with dry sand or dirt.
4. Beware the Lethal Tire Pyrolysis Explosion (1,000+ kPa / 150+ psi Blowout): When radiant heat from a 550°C brake drum bakes a heavy truck tire (690 to 760 kPa / 100 to 110 psi), the inner rubber liner undergoes thermal decomposition (pyrolysis), releasing flammable hydrocarbon gases inside the sealed tire casing. Even after you extinguish outside flames, internal tire pressure can exceed 1,400 kPa (200+ psi) and self-ignite inside the tire 5 to 30 minutes later, blowing the sidewall or steel wheel rim apart with lethal force. Always approach a hot or smoking truck wheel from a 45-degree angle toward the front bumper or rear bumper (looking at the tire tread), NEVER standing directly perpendicular to the flat steel wheel rim or sidewall.

Phase 5: Special Guidance for RVs, Motorhomes, and Pickup Trucks Towing Heavy Trailers¶

Non-commercial drivers operating Class A/C motorhomes or heavy-duty pickup trucks towing 4,500 to 7,000 kg (10,000 to 15,000 lb) travel trailers, horse trailers, or boats suffer mountain brake fade even faster than commercial semi-trucks because hydraulic disc brake fluid boils at 200 to 260°C (400 to 500°F):

1. Use TOW/HAUL MODE + Manual Gear Lock (M1 / M2 / L) Before the Descent: Press the TOW/HAUL button and use the manual ± gear selector on your pickup or RV shifter to lock the transmission into 2^nd or 3^rd gear before starting down a steep pass. If your diesel pickup or diesel pusher RV has a dashboard EXHAUST BRAKE button, turn it ON at the summit.
2. How to Use Your Electric Trailer Brake Controller Properly on a Mountain Grade: Never ride the manual slider bar on your dashboard trailer brake controller continuously down a grade; that burns up the trailer's electric drum magnets and boils the wheel bearing grease within minutes while leaving your truck brakes cold. Verify your controller's Gain (6.0 to 8.0) is set properly so both truck and trailer brakes share the load equally during brief, firm 3-second Snub Braking applications, then release the foot pedal completely so both systems cool.

Frequently asked questions¶

Should I shift a manual heavy truck into a lower gear if my brakes start fading halfway down a mountain pass?¶

No, never depress the clutch or pull a non-synchronized heavy truck transmission out of gear once your truck is already accelerating out of control on a steep downgrade. As soon as the transmission enters Neutral on a steep grade, gravity accelerates the heavy truck so rapidly within 1 to 2 seconds that matching engine RPM to road speed becomes physically impossible, leaving you freewheeling in Neutral with zero engine braking. Keep the truck locked in whatever gear it is currently in, switch the Engine Compression Brake (Jake Brake) or retarder to its maximum setting (Stage 3), turn on your 4-way hazard lights and horn, and steer into the next Runaway Truck Ramp.

What is the correct "Snub Braking" technique for descending a steep mountain grade in a heavy truck or RV?¶

The Federal Motor Carrier Safety Administration (FMCSA) Snub Braking method requires selecting a low enough transmission gear at the summit (before starting down the hill) and turning on your engine brake so the truck accelerates slowly. Choose a safe target speed for the grade (for example, 55 km/h or 35 mph). When the truck reaches your target speed of 35 mph, apply the service brakes firmly for 3 to 4 seconds just long enough to reduce your speed by 8 km/h (5 mph) down to 30 mph, then release the foot brake pedal completely so cold air cools the drums while the engine brake holds the load. Repeat this 5-mph snub cycle as needed; if the time between snubs drops below 10 to 15 seconds, you are in too high a gear and must stop safely in a turnout to select a lower gear.

Will a Runaway Truck Ramp flip my tractor-trailer over, and do police issue a ticket for using one?¶

Runaway truck ramps (pea-gravel arrestor beds) are specifically engineered by highway authorities to stop an 80,000-pound (36,287 kg) semi-truck entering at 130 to 160 km/h (80 to 100 mph) without rolling over, provided you line up the tractor and trailer dead-center and straight before hitting the gravel. As the tires sink 45 to 60 centimeters (18 to 24 inches) into the loose river gravel, the gravel walls hold the wheels straight while absorbing kinetic energy at 0.4 to 0.8 G. Law enforcement agencies generally do not issue traffic tickets simply for using an escape ramp (as they want drivers to use them rather than crashing), though you will pay a heavy-wrecker winching fee to extract the rig safely from the gravel bed.

Why do semi-truck tires and brakes often catch fire several minutes after the truck has already come to a safe stop?¶

While a heavy truck is moving at highway speed, the high-velocity windstream rushing through the wheels prevents flames from taking hold even when the cast-iron brake drums reach 550 to 600 degrees Celsius (1,000 to 1,100 degrees Fahrenheit). The instant the truck stops in a runaway ramp or on the shoulder, cooling airflow stops completely, and intense stored heat inside the thick iron drum conducts inward into the wheel hub oil seal, bearing grease, and rubber tire bead, igniting a wheel-end fire within 2 to 10 minutes. In addition, extreme radiant heat decomposes the rubber inside the sealed tire (pyrolysis), building explosive internal pressure that can blow the tire and steel rim apart even after outside flames are put out; always stand upwind and approach hot wheels only from a 45-degree front or rear angle, never facing the side of the wheel rim.

Sources checked¶

• Federal Motor Carrier Safety Administration (FMCSA) (United States): Commercial Driver's License (CDL) Manual: Section 2 (Mountain Driving Snub Braking, Escape Ramps) and Section 5 (Air Brake Thermodynamics, Pushrod Stroke Limits).
• National Highway Traffic Safety Administration (NHTSA) & FHWA (United States): Grade Severity Rating System (GSRS) for Heavy Trucks and Pea-Gravel Arrestor Bed Runaway Truck Ramps.
• National Transportation Safety Board (NTSB) (United States): Highway Special Investigation Reports on Commercial Vehicle Mountain Grade Brake Fade and Runaway Ramp Utilization.
• Commercial Vehicle Safety Alliance (CVSA) (North America): Out-of-Service Criteria for S-Cam Brake Pushrod Stroke, Thermal Drum Cracking, and Wheel-End Fire Prevention.

Related guides¶

• Brake failure while driving: emergency stopping protocols
• Trailer sway, fishtailing, and towing brake controller emergencies
• Clutch failure, transmission limp mode, and stuck in gear on highway
• Stuck accelerator, runaway car, and unintended acceleration
• Emergency numbers by country