A car can go up to 75 mph in 5 seconds
At 60 MPH you would travel 88 feet per second. 5 x 88 = 440 feet in five seconds.
The distance behind the car you are following
If by this you mean only "hot heat" when drive at highway speeds likely thermostat bad and/or almost stuck and takes long time warm up from high engine RPM during highway driving.
Cars are rated as to how efficient they are. The government gives them two ratings; Highway mileage and City mileage. City mileage is determined by driving the car at slower speeds and stopping and starting many times. This consumes a lot of fuel during the times the car is not moving or having to accelerate. Highway mileage is determined my driving the car long distances at highway speeds, usually 55 mph or more.
It would shorten the life span of the engine some.
Common cars can't do highway speeds (65 mph) in first gear and many have rev limiters.
Need more info like what is the vehicle doing when it shakes, is it idling in park, driving down the road, braking, driving at highway speeds, etc.
First the car engine and thus the air conditioning compressor are running faster at highway speeds, so the unit is capable of more cooling. Second highway speeds force more air over the condenser coils which are in the front of the car, which means they are more efficiently cooled by the outside air thus allowing the system to more efficiently cool the inside of your car. You might want to check the "charge" of the system if it gets really cold on the highway, and is less than adequate in the city.
increases the distance needed to stop your car
At freeway speeds, only a fool breaks the two second rule. Let the car in fromt pass an obstacle, sign, roadmarker or similar and you should pass it not less than two seconds later. At urban speeds one and a half to two car lengths.
Usually highway driving is where a car gets the most mpg.
2 to 5 seconds, depending on what speed you are travelling and the weight of your vehicle. The faster you go or the heavier your vehicle is, the more distance you should have between vehicles. Check the time by taking note of some landmark such as a sign or overpass, and when the car in front reaches it, start counting seconds. When you pass that same landmark, stop counting. If you're doing city speeds (around 30mph/50kph), you should have 2 or 3 seconds between. At highway speeds (around 60mph/100kph), you should have more like 5 seconds between.
He was recklessly driving the car on the Highway.