Vehicle Operations and Driving on Public Roads
The loaded tender behaves differently
A mobile water supply apparatus has a high center of gravity and a large moving mass. Baffles reduce surge but do not eliminate it. Liquid movement shifts weight forward during braking and sideways in turns, so the driver must slow before curves, brake earlier, and avoid abrupt steering. Use a following distance of at least 4 seconds in good conditions and more when loaded, wet, or dark. Check bridge weight limits, clearance heights, and overhead wires. At railroad crossings, stop as required, look, and listen; do not rely on the siren to clear the path.
Emergency response
Lights and siren request the right of way; they do not grant it. Approach intersections at a speed that allows a stop, scan left-right-left, and expect other drivers to misjudge your size and stopping distance. Use a spotter when backing, and stop if you lose sight of the spotter. In ice, snow, or rain, reduce speed and increase following distance; a loaded tank increases stopping distance and rollover risk.
Worked example
A 2,000-gallon tank adds about 16,700 lb of water. On a 35-mph curve, the driver who enters at 35 mph and brakes mid-curve asks the tires to both slow and turn a top-heavy load. Correct reasoning is to slow to a safe entry speed before the curve, keep steady steering, and accelerate gently only after the curve.
Traps
Do not assume baffles stop all surge. Do not use a retarder or engine brake on slick surfaces if it could cause drive-axle slip. Do not back without a spotter, and do not treat a green light as a guaranteed clear intersection.