4WD Vehicles and Off-Pavement Travel Safety

Stay on established roads and drive with a high clearance vehicle or you may have a bad day like this motorist.

NPS

You are responsible for your own safety.

In this remote place, you must be able to self-rescue and self-reliance is essential. Mojave National Preserve is a scenic wonder but it is also a truly rugged place. A visit here means leaving the safety net of the modern world behind. Be sure to check current road conditions and vehicle requirements before heading out.

The information that follows is not designed to scare potential visitors out of visiting the Preserve, but remind everyone that traveling into the Preserve isn't to be taken lightly. Rangers want to be sure motorists understand that travel here requires specialized vehicles, equipment, and planning to avoid or recover from a mishap. Improper planning could result in getting stuck and paying a very expensive third-party towing company. The fact that you are reading this means you are the right track as you prepare for a safe visit.

 

Most rescues involve vehicles stuck in the sand.

NPS

Staying with your car is the most important thing you can do in the event of an emergency. People have died from exposure trying to walk back to the paved roads.

Appropriate vehicles and equipment in good working order and adequate supplies are critical. Roads are narrow, sandy, and winding. Travelers need to be prepared for their trip and understand the guidance below. Unpaved roads vary in difficulty. Not all vehicles are right for travel for off-pavement travel in the Preserve.

Most rescues involve vehicles stuck in the sand. Other rescue reasons include flats where rocks ripped up tires only rated for street use. Additional reasons include vehicles getting stuck in mud or high-centered on uneven road beds, or vehicles suffering some kind of mechanical breakdown.

Scroll to the bottom of the page for definitions of terms like All-Terrain tires, the difference between a high clearance and very high clearance 4x4, and what a short wheelbase is.

 

Prepare for the unexpected.  Extended break downs could have you stuck in the park after dark.

NPS

Recommended Safety Equipment and Supplies

A high clearance 4x4 with tires designed for off-pavement use is the most important safety item you need.

• Return plan filed with friend or relative.

• 24-hour Emergency or Missing Persons [phone] (Intergency Dispatch) Non-emergency use [phone] during business hours.

• Shovel to smooth off cut banks or dig out of sand

• Jack to lift vehicle with a base that can be set up on rocky or sandy ground

• All-Terrain spare tire
• A second spare tire

• Extra food, water, and any needed medications to last several days

• Hot/cold weather clothing

• Satellite Phone or Satellite Messenger such as a Garmin InReach

Roads Risk Assessment

Use roads at your own risk.

Many dirt roads lead to isolation. They do not lead to visitor centers, cell phone service, hotels, stores, or gas stations. Depending on the time of the year and the roads you are on, you may not see another vehicle the entire time you are out there.

While very rare, people have died here while many others were rescued just in the nick of time. They didn't fully appreciate the risks, traveled in a vehicle not equipped for the conditions on a remote, seldom traveled road, or didn't let anyone know where they were going. They lacked a satellite communication device to call for help and didn't pack enough equipment, warm clothing, food, or water.

Do not overestimate the capability of your vehicle. Some roads are fine for stock high clearance 4x4 pickups and SUVs. Third party tow bills often reach hundreds or thousands of dollars. Rangers are happy to provide you advice about a trip plan or to discuss your equipment. Contact Us

Always assume the road will get worse ahead. If it gets too rough for you, turn around!

 

Potential Road Hazards

Road Conditons: Due to the sheer size of the region and the number of roads in the Preserve, it is not possible to provide updated travel conditions. Expect and be prepared for poor conditions. Don't go if it looks bad or rain is forecast.

Summer Weather: During the summer monsoon season (June - September), it is better to travel in the morning. Storms usually occur after 1pm.

Winter Snow and Ice: Planning on travel in areas above 3,000 feet? Check road conditions with a ranger. Contact info at the bottom of the page. Roads at this elevation may be saturated from rain or snow and impassible. There are very few people to help you if you break down. Temperatures can drop well below freezing. The short days of winter surprise hikers who may need to finish their hike by headlamp.

Cattle: This is ranch country. Expect cattle standing in the road on blind corner and especially in the dark. Black cows on a moonless night have resulted in many accidents where people were driving too fast for the conditions.

 

Tires Defined

All-Terrain/Mud Terrain Tires: For full size vehicles the ideal tire is a good condition E-Range All-Terrain tire. Examples of All-Terrain tires include BF Goodrich AT/KOs, Cooper ST-Maxx tires, Firestone Destination ATs, etc. This is a tire that has a very thick rubber tread, more flexible rubber, and much stronger steel belts inside the rubber to handle driving over rocks. Load range E is equivalent to a 10-ply tire, where there are 10 layers of reinforcement in the tire. Load Range D tires are equivalent to 8-ply tread, and C is equivalent to 6-ply tread. You also want 3-ply sidewalls on your tires as the rougher roads have rocks along them that will rip open thinner sidewalls.

Mud-terrain tires are not effective at handling mud in the Preserve. The local clay packs into the spaces between the knobby treads like peanut butter. It isn't flung out by the revolution of the wheel like watery mud in other regions of the country. Mud-terrain tires turn into slick, smooth donuts that have no traction in mud in this area.

Rugged Spare Tires: If you plan to spend a lot of time on unpaved roads, your vehicle needs at least one All-Terrain spare tire. Most stock spare tires are thin and will blow out after only a few miles on a rocky road.

Do you need 2 spare tires? Motorists occasionally scrape and rupture the sidewall of a front tire against a rock along the road. Then before they realize what happened they also rip open the sidewall on the rear tire on the same rock. This has caused many double flats.

Street Tires: These are normal automobile tires. They are designed for pavement only. Their rubber is thinner than all-terrain tires. The rubber is stiffer, and often equivalent to 4-ply tread with 1-ply sidewalls. Street tires may ride more comfortably on pavement and last longer, but they are far more likely to rupture off-pavement.

 

Rental 4WD Warning

Rental 4x4 trucks and SUVs often come with street tires not designed for off-pavement use. Just because the vehicle is a 4x4 doesn't mean it has the right tires. Check the sidewall to see if it says "All-Terrain."

 

Deflate your tires before your vehicle gets stuck in the sand to avoid this.

NPS

Tire Pressure

Lowering the tire pressure greatly increases traction by flattening out the tire.

Many new vehicles including pickups come with tire pressures up to 75 pounds per square inch. This is very high pressure. Many off-road motorists lower their tire pressure to 20 psi when traveling on soft sand, then fill the tire back to recommended pressure when they return to pavement. The risk with highly pressurized tires on unpaved roads are blowouts. As tires go over rocks they are so rigid from the high pressure they can't flex and absorb rocky surfaces, so instead they rupture.

What is the difference between a 4x4 and All Wheel Drive (AWD) vehicle?

True 4x4 vehicles have a 'transfer case' in the drivetrain that puts full engine power to the front wheels. All Wheel Drive, common on vehicles like crossover SUVs, relies on a 'differential' to send variable power to each wheel. AWD is good on level roadbeds in low traction conditions like snow. It is not designed to fully power the front tires in off-pavement rugged situations. For example, if the road goes up a steep hill and there is a lot of loose rock in the road, fully powered front wheels are needed to rotate strongly and pull the vehicle up the slope. AWD cannot do that very well and may fail.

Clearance Defined

High Clearance: Any factory stock full or mid-size 4x4 pickup or SUV. Running boards, step bars, and plastic bumpers can get ripped off when going over rough sections. Moderate-clearance crossover vehicles as well as some station wagons designed for off-pavement used would be considered Medium Clearance and can travel many Preserve roads so long as they are equipped with off-pavement tires.

Very High Clearance: Factory vehicles are considered very high clearance. Also included are 4x4s with aftermarket suspension lifts and taller tires.

Low Clearance: Any car, minivan, or RV, and many SUV 'crossover' vehicles. None of these are designed for Preserve roads, even with off-pavement tires as they sit low to the ground and can scrape off plastic trim or engine components like the oil pan.

Wheelbase Defined

Short Wheelbase: These are vehicles where the front and rear axles are closer together, as well as 4x4 pickup trucks with a short bed (less than 6' long) and a regular cab. Short wheelbase vehicles create a situation where the rear tires start to climb a hump in the road or obstacle before the front tires go down the other side. This lifts the center of the vehicle up and over the hump, preventing scraping.

Long Wheelbase: These are vehicles where the front and rear axles are further apart. This includes longer SUVs designed for 7-9 passengers or 4x4 pickups with a crew cab and/or long bed. Long wheelbase vehicles create a situation where the rear tires haven't yet reached the hump in the road but the front tires have already cleared the hump. The vehicle can high center and get stuck.

Entry/Departure Angle: Short wheelbase vehicles simply are shorter, making getting through a wash easy. Long wheelbase vehicles may be too long and hang up on the front or rear bumper.

Bumpers and Running Bars Defined

Bumpers: If you have a stock front bumper look at how close the bumper is to the ground. On rough 4x4 roads, hazards like boulders, deep ruts, or hard centerline ridges in the road can rip off the bumper. Vehicles designed for rugged off-pavement use have had the lowest parts of the front bumper's air dam removed, or a custom bumper installed that is much higher off the ground. If you drive into a wash at a steep downward angle that suddenly pitches up to leave the wash, this scrapes the bumper against the roadbed, which will scrape and damage the bumper.

Running Bars/Step Bars: Like low bumpers, these bars along the vehicle are used to step easily into a truck or SUV. They reduce clearance and can be damaged or ripped off on rough roads. However, they can also absorb most of an impact and protect the vehicle's body and doors.