Tanker trucks, which are sometimes called mobile water supply apparatus, are used to transport water and firefighters to many emergency scenes, especially to emergency scenes where water is not readily available. Unfortunately, the fatality rates of these lesser-used firefighting vehicles is much higher than the accident rate of other firefighting vehicles.

According to some industry experts, part of the problem may be laws regarding drivers.
Most state laws allow emergency vehicle drivers important exemptions. Drivers of these vehicles are allowed to speed, drive against the flow of traffic, request right of way, and to drive around traffic control items. All these exemptions permit driver to help people in an emergency, but these exemptions are not meant to permit reckless driving. Drivers of mobile water supply apparatus are still expected to be cautious of the public.

For example, while drivers are permitted to exceed the speed limit when driving mobile water supply apparatus to an emergency, drivers must also consider road conditions when deciding how fast to drive. Some fire departments have rules about how quickly drivers operating mobile water supply apparatus can drive. However, experts argue that these limits do not go far enough and drivers should never drive more than 10 mph over the posted speed limit, even in ideal conditions. As well, sharp turns, residential areas, pedestrians, and school zones need to be considered when deciding on an appropriate speed.

It is expected that when the driver of a mobile water supply apparatus approaches traffic, he or she will leave enough room to respond safely to the actions of other drivers. The amount of space that needs to be left will depend on the speed of traffic and the speed of the mobile water supply apparatus tanker truck. Driving too close to other vehicles often leads car accidents causing fatalities and serious personal injuries. If a passenger car driver panics and brakes or slows suddenly, the tanker often cannot stop in time and may cause a rear end collision.

Driving against the flow of traffic is something that most drivers of mobile water supply apparatus tanker trucks must do on occasion to get to an emergency site quickly. However, it is important for drivers not to force right of way. Drivers must make sure that oncoming lanes are clear and that drivers see the emergency vehicle. Trying to force right of way usually results in head on collisions. When driving against the flow of traffic emergency truck operators must drive more slowly and must be prepared for unexpected obstacles.

When driving through intersections and around traffic control devices, drivers of mobile water supply apparatus tanker trucks must ask right of way. They must stop at red lights and ascertain that drivers are willing to offer right of way. They must also ensure that all drivers see the emergency vehicle and respond. Many accidents occur in multiple lanes, where one passenger vehicle driver does not see the emergency truck but the truck driver assumes that it is safe to proceed.