1. Chapter 16 Speed Management -Operating at the appropriate speed for all road conditions. -Condition of road. -Visibility. -Traffic speed and flow. -Perception distance. -Reaction distance -Brake lag distance. -Braking distance.
2. Perception Distance -Distance a vehicle travels from when you see the hazard to when your brain recognizes it. -Alert driver is ¾ of a second. -55mph a vehicle travels 60 feet in ¾ of a second.
3. Reaction Distance -Time from when your brain tells you to hit the brake pedal to when you do it. -Another 60 feet traveled.
4. Brake lag distance -Take about ½ second for the mechanical operation to take place. Braking Distance -Distance for vehicle to stop once brakes are applied. -Affected by weight, length, speed and road conditions. -At 55 mph, heavy vehicle travels 170 feet and takes about 7 seconds to stop.
5. Speed and Surface Conditions -Traction is key Rain -Mixes with oils on the road. -Layer of oil between tires and the road. -Can last from few minutes to few hours. -New pavement is more slippery than old. -Heavy rain can cause a vehicle to hydroplane.
6. Speed and Surface Conditions Snow -Reduced traction, limited visibility. -Reduce speed by at least ½ in snowy conditions. -Make sure you can safely stop and maneuver if needed.
7. Speed and Surface Conditions Icy Roads -Be alert for Black Ice. -Appears to be wet when it is really icy. -Check mirrors for ice. -Drop speed by ½ on icy roads. -Bridges can freeze easily. -Avoid any changes while driving on a icy bridge.
8. Speed and Road Shape Curves -Driving through a curve too fast can cause you to flip. -Slow to at least 5mph below posted sign. -Braking in a curve can be dangerous. You may lock your wheels and cause a skid. -Never exceed posted limit.
9. Speed and Road Shape Grades -Gravity and vehicle weight play a part. -Upgrade = vehicle works harder. -Possibly shift to a lower gear. -Downgrade = vehicle works with gravity, gains more speed. -Use care in maintaining a safe speed.
10. Speed and Traffic Flow -When traffic is heavy, safest speed is the speed of traffic. -If unable to maintain safe following distance, slow down by 3-4 mph. -Passing traffic increases chances of an accident.
11. Obeying Speed Limits -Based on principles of good speed management. -Reasons for not speeding are… Accidents -More likely to happen at higher speeds. -Higher speeds in accidents = high chance of fatalities.
12. Obeying the Speed Limit Penalties -Two or more convictions can disqualify you from diving a Commercial Motor Vehicle. -Speeding convictions become part of your permanent record. -Can be very costly. -Tracked by insurance carrier.
13. Obeying the Speed Limit Maintenance -Tires and brakes wear out faster at higher speeds. -Speed goes up, so does costs. Fuel Economy -Tractor trailers are not race cars. -Adjusting your speed can positively affect you fuel economy. -It’s worth it to drive a little slower.
