Speed, Night Driving, Highways, Skids, Weather, Roundabouts and Floods

Written for aiforu2 as the source for a practice-test bank and the on-device tutor for the Texas Class C knowledge exam. The facts follow the official handbook; the wording is ours.

Source: Texas Driver Handbook (DL-7), Texas Department of Public Safety, rev. January 2026, chapter 8 "Speed and Speed Limits" (pp. 45–46) and chapter 9 "Some Special Driving Situations", first part (pp. 47–50).

Speed and following distance

Drive at about the speed of the main stream of traffic, always know how fast you are going, and never exceed the limit. The faster you go, the more room you need ahead: at 30 mph or less, keep at least two seconds behind the car in front in good conditions; above 30 mph, keep four seconds; in poor conditions allow more. Four seconds is the best practice for a beginner. To measure it, watch the vehicle ahead pass a fixed object; if you reach the same object in less than the interval, you are following too closely.

It takes the average person 1½ seconds to think, react and apply the brakes. Total stopping distance, with good brakes and tires on dry, level pavement:

Adjust speed and following distance to your own condition and the vehicle's; if you are tired or unwell, do not drive. Slow down and add distance when the road is wet (a little rain makes it slippery and the car harder to control), when it is crowded, and when vision is limited: you must always be able to stop within the distance you can see ahead, so never over-drive your headlights or the weather.

Speed narrows what you see. Standing still your field of vision is 180 degrees or more; at 20 mph it drops to about two-thirds, at 40 mph to about two-fifths, and at 60 mph to about one-fifth.

Speed limits

Obey posted minimum and maximum limits, and slow below them in heavy traffic, bad weather and poor visibility. Cities and counties may change the limits, but a limit must be the same by day and by night. The statutory maximums for passenger vehicles and light trucks, unless posted otherwise:

The Texas Transportation Commission, regional mobility authorities and local governments may raise or lower limits after traffic studies; many limited access highways are posted at 75 up to 85 mph. Always follow the posted limit.

Slow down or move over

When an emergency medical vehicle, law enforcement vehicle, fire truck, tow truck, utility service vehicle, or a TxDOT or other highway construction or maintenance vehicle is stopped on the road with its lights on or flashing, you must either slow to 20 mph below the limit or, on a road with several lanes in your direction, move out of the lane next to it. Mail, delivery and trash-collection vehicles also stop often in the road: slow down, and change lanes before passing them if you can.

Street racing

Racing, speed competitions, drag or acceleration contests, endurance tests of a driver, and speed exhibitions or record attempts connected with a drag race are all illegal. Racers cannot react to ordinary hazards, and their engines tear up the asphalt at taxpayers' expense. The criminal penalty runs from a Class B misdemeanor to a second-degree felony.

Night driving

Night driving is far more dangerous; many people see poorly after dark, so travel by day when you can and never drive tired. Slow down so you can stop within the distance lit by your headlights. Headlights are required from 30 minutes after sunset until 30 minutes before sunrise, and whenever people or vehicles cannot be seen clearly at 1,000 feet. Do not stare into oncoming headlights; look down toward the lower right side of your lane. Use low beams within 500 feet of an oncoming vehicle, when following within 300 feet of another vehicle, on lighted roads, and in fog, heavy rain, sleet, snow or dust. If you must park on an unlit highway at night, leave the parking lights or low beams on.

Highway driving

A highway in Texas is the whole width between the boundary lines of a publicly maintained way that is open to vehicles. Freeways, tollways and expressways are built for safety, but you must use them properly. Plan the entrance, direction and exit in advance, and make sure you and the car are fit for it; if you cannot or will not drive at or above the minimum limit, stay off.

• Entering: yield to traffic already on the highway. Use the speed-change lane, keep right, signal left, and when it is clear speed up to match the flow and merge.
• Choosing a lane: the right lane for the minimum limit or slower than the flow; the middle or left lanes when faster than others or passing; move to the exit lane early if you are leaving soon; obey signs assigning lanes.
• In your lane: stay in the middle of it, do not weave, hold a constant speed with the traffic, keep at least two seconds behind (four in bad weather), watch several cars ahead for sudden stops, adjust speed to let others enter, and in any lane except the right one be ready to move over for faster traffic.
• Leaving: move to the proper lane well in advance, earlier in heavy traffic; exit signs usually appear at least 1,000 yards ahead. Slow on the ramp so you are within the new limit when you leave.

Highway hypnosis is drowsiness or unawareness brought on by monotony and the steady hum of wind, engine and tires. Fight it: stop at least every two hours or 100 miles and walk around, drive no more than eight hours a day, and keep your eyes moving between near and far, left and right, the signs and the mirror. Other habits: keep a window open for fresh air, wear good sunglasses on bright days and never at night, stay out of other drivers' blind spots (behind or past, never alongside), and avoid the phone: pull off the road or use a hands-free headset, and if you are under 18 any use, even hands-free, is illegal except in an emergency.

Breakdowns

If you cannot get the car off the road, get everyone out and away from the road and set out portable warning devices. Otherwise move the car onto the shoulder; a car with a flat or blowout can be driven slowly off the road. Turn on the hazard flashers (or taillights), and at night the interior lights too. Tie a white cloth to the antenna or door handle, or raise the hood.

Controlling the car in special situations

The one rule for every situation: think before you act.

• Skid: the tires have lost their grip. Do not brake suddenly or hard; ease off the gas and steer in the direction of the skid, straightening gently as control returns. Avoid skids by slowing in poor conditions and keeping good tires.
• Brake failure: do not panic. Use the parking brake, cautiously so the wheels do not lock and skid, and shift to a lower gear.
• Running off the pavement: do not brake hard. Grip the wheel, ease off the gas, brake gently, and do not swing back onto the road; wait until you have slowed, check behind, then steer back carefully.
• Flat tire or blowout: no hard braking; ease off the gas, brake gently, and steer straight ahead to a stop.
• Steep hill: shift to a low gear to help slow the car. Never coast in neutral, and with a manual never coast with your foot on the clutch.

Winter driving

Increase the interval from the vehicle ahead to match the pavement; many rear-end crashes on ice happen because drivers leave no room to stop, and snow tires still slide on ice or packed snow. There is no "safe" speed on snow or ice: be extremely cautious until you learn how much traction you have, and avoid locking the brakes, which costs you steering. Clear all snow and ice from the windows before driving, even a short way, and check the wipers and defroster. Watch for danger spots: bridges ice when the rest of the road is clear, and snow melts more slowly in shade. Start out very slowly (spinning the wheels only burns rubber), test the brakes gently once moving, and slow before turns. Chains are the most effective aid where ice and snow stay on the road, but neither chains nor snow tires allow normal speeds on slick pavement.

Roundabouts

A modern roundabout is a one-way circular intersection where traffic flows counterclockwise around a center island, controlled by yield signs rather than signals; it has 8 conflict points against 32 at a four-way signalized intersection and cuts severe crashes by about 80 percent. Slow down on the approach and obey any advisory speed, yield to traffic already in the circle, enter when there is a gap, go counterclockwise, and signal a right turn to exit. Watch for cyclists and pedestrians in the crosswalks on the approaches and exits. In a multi-lane roundabout, pick the entry lane from the advance lane sign and do not change lanes inside the circle. Give trucks, buses and fire trucks room, since they may need more than one lane. Pull over for an emergency vehicle on the approaches or exits, but never stop inside the circle: clear it first, then pull over.

Floods

Nearly half of all flash-flood deaths are vehicle-related. Six inches of water reaches the bottom of most cars and can cause loss of control or stalling; twelve inches floats many cars; two feet of rushing water carries away pickups, SUVs and most other vehicles. Water can hide a missing piece of roadbed or bridge, and a road weakened by flooding can collapse even after the water recedes. If the car stalls in floodwater, get out quickly and move to higher ground. Better: when there is water on the road, Turn Around Don't Drown, and take another route.

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