Do computer racing games encourage young people to speed?

No, kids are intelligent enough to know the difference between computer games and real life. Blaming computers is the easy answer to a problem that is much more complex.

Yes, they blur the boundaries of the computer world and real life and this inevitably leads to kids speeding

There has been no proof that computer games influence people to that extent so probably not. However, computer games manufacturers should make sure they don't go too far in making their games realistic.