The dictum «Driving to the airport is the most dangerous part of gliding.» is not only misleading, because driving by car or riding a bike cannot be compared with flying, it's plainly wrong.
When flying, we find ourselves in an environment human is not adapted to—namely air—flying with a speed requiring smooth deceleration in order to survive. The bar is raised further by physological strains, like thin air and intense temparature variations, and psychological burdens, ranging from time pressure to the well known peer group pressure.
In general (club) gliding, these latent risks manifest themselves in approximately 14 fatal accidents per 1M flights, in alpine gliding even more thant 30 fatal accidents per 1M flights.
The following chart shows the trend of the accident rates in Germany over 13 years, Switzerland showing similar numbers for non-alpine gliding in the same timeframe. (Source: BFU)
For comparison only: The accepted definition for 'safe sports' tolerates a risk of 1 fatal accident per 1M flights.
In order to prevent these potential hazards from becoming accidents, rules and more advanced approaches, which deal with human beings being prone to errors.