In 2004, women's life expectancy exceeded men's life expectancy by 5.2 years, the smallest gender gap in life expectancy since 1946. Life expectancy for whites was five years greater than that of blacks. Life expectancy for black and white men and women was as follows: 1  Black male: 69.8 years.  White male: 75.7 years.
But, that's not always the case. Safe following distances vary according to traffic speed and weather conditions and according to the type of vehicle you're driving. In good conditions, you should allow 2 seconds between your car and the vehicle in front of you. Here's an easy way to work that out.
A big factor in this distance is the relative speeds of the two vehicles. As a point of reference, consider that on a public highway, if the vehicle to be passed is traveling at a speed of 20 or 30 mph, the minimum recommended passing-sight-distance for the passing vehicle is 800 or 1100 feet, respectively.AUL ROAD INSPECTION HANDBOOK Note: Scales are for feet or meters; to extend range, multiply or divide all scales by 10. Example: For a chord of length, C, of 600 feet, and a Middle Ordinate, M, of 20 feet, the radius of the curve is 2260 feet.