For real though, cars feel big and we aren't equipped to understand speeds above like 25 mph. It's easy to think that in a standard sized car there is only like a foot or two on either side of your car and the other lanes and that each of those dashed lines on the pavement are just a couple feet long. In reality almost all cars and standard duty trucks and vans are less than 7 feet wide, most are closer to 6 and the lane itself is 12 feet wide. Each of those dashed lines is 10 feet long and twenty feet separates each line.