Interstate Rain, Worn Rear Tires, and a Tailgating Student
You are on I-65 with a 16-year-old probationary-license holder during a steady rain. The school's 2018 sedan has front tires at 7/32 inch and rear tires at 3/32 inch. The student has set cruise control at 60 mph in a 55 mph zone and is following a semi-trailer at about two seconds. Spray from the truck limits visibility, and the wipers are on intermittent. The student says, 'I stay close so I can see the truck's taillights.' A bridge deck ahead looks darker and wetter than the pavement. The student has not braked since entering the interstate and is gripping the wheel tightly. Traffic is moderate, with a box truck to the left and a shoulder that is narrow and partly flooded. The student's route plan called for 20 minutes of interstate practice, but you have already been out for 35 minutes.
1. What immediate coaching should you give, and what hazards are you managing?
Read the worked answer
Coach immediately: 'Off cruise, ease off the accelerator, increase gap.' The student should disengage cruise because cruise control can cause wheelspin or delayed response on wet pavement. At 60 mph in rain, two seconds is far too close; aim for at least four seconds, and more behind a truck that throws spray. Move left or right only after checking the box truck and mirror; do not hang close to the trailer just to see taillights. Approach the darker bridge deck with a gentle lift, not a hard brake, because wet bridge decks can be slicker and hard braking can trigger a skid. Keep steering smooth and look far ahead. The student's tight grip and lack of braking show tension and limited scanning; prompt mirror checks and a commentary of hazards. If visibility drops or the car feels light, slow further and consider leaving the interstate.
2. How should you explain hydroplaning and the tire condition to the student, and what should the school do about the car?
Read the worked answer
Hydroplaning occurs when water lifts the tires off the pavement faster than the tread can evacuate it; speed, water depth, tire tread, and tire pressure all matter. The rear tires at 3/32 inch are worn and much less able to channel water than the front tires at 7/32 inch. A rear-tire hydroplane can cause a sudden rear slide, and a new driver is likely to overcorrect. The 2/32-inch legal minimum is not a performance standard for wet weather; 3/32 is marginal and, combined with rain, makes this car unsuitable for the interstate lesson. The school should remove the car from training service until the tires are replaced, check pressures and wiper condition, and document the defect. The student should be taught that tread depth, speed, and standing water are a risk chain-not just 'drive slower in rain.'
3. Should the lesson continue? What should be recorded and taught next?
Read the worked answer
End the interstate portion at the next safe exit and debrief in a calm location. The lesson objective was 20 minutes of interstate practice; continuing to 35 minutes in worsening conditions with a worn-tire car adds risk without teaching value. In the record, note the rain, the tire measurements, the cruise-control error, the following distance, the bridge-deck hazard, and the decision to terminate. Submit a maintenance request and notify the owner that the car must not be used until tires are replaced. For the next lesson, teach: no cruise in heavy rain, four-second following, spray avoidance, smooth brake/steer inputs, and bridge-deck awareness. Also review the student's route plan and decision-making-recognizing when to shorten a lesson is part of defensive driving.