22. Including reaction time, the stopping distance is more than 20 feet at 10 miles per hour, at 20 miles per hour it will be about: Choose one a. 30 feet b. 63 feet c. 40 feet d. 75 feet

The stopping distance of a vehicle includes both the **reaction distance** (the distance traveled while the driver reacts) and the **braking distance** (the distance it takes to bring the vehicle to a complete stop once the brakes are applied). Generally, as speed increases, the braking distance increases **quadratically** (i.e., it increases with the square of the speed), while the reaction distance increases **linearly**. Given: - At **10 mph**, the stopping distance is more than **20 feet**. - At **20 mph**, doubling the speed doesn't just double the stopping distance; it significantly increases due to the quadratic relationship. Using standard estimates: - At **20 mph**, the total stopping distance typically ranges around **60 feet**. **Therefore, the most accurate option is:** **b. 63 feet**