Managing Space
Managing Space tests following distance, side and rear space, and overhead clearance. The exam expects a specific following-distance formula, not a vague leave-room answer.
Following distance formula
Use at least one second for each 10 feet of vehicle length at speeds below 40 mph. Above 40 mph, add one second. For a 60-foot combination at 55 mph: 60 ÷ 10 = 6 seconds, plus 1 = 7 seconds. Add more for rain, snow, darkness, or heavy traffic. Count by choosing a fixed object and saying one thousand one, one thousand two as the vehicle ahead passes it.
Space around the truck
Keep space ahead, behind, and to the sides. At intersections, stop so you can see the rear tires of the vehicle ahead and have room to steer around it. Do not pass close to parked cars or pedestrians. Check overhead clearance before entering a bridge, tunnel, or canopy.
Worked example
You drive a 50-foot vehicle at 45 mph on a dry road. Reasoning: 50 ÷ 10 = 5 seconds, and because 45 mph is above 40, add one second = 6 seconds. In rain, add another second or more.
Traps
Using a fixed two-second car gap, forgetting to add for speed, and ignoring side clearance are common. Space is your escape route; if you cannot stop, you need a place to go.