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.
HIGHWAY DESIGN MANUAL 200-3 May 7, 2012 distance (m) from centerline of inside lane to the obstruction. See Index 1003.1(12) for bikeway stopping sight distance on horizontal curve guidance. When the radius of curvature and the clear distance to a fixed obstruction are known, Figure 201.6 also gives the sight distance for these conditions.