The conventional wisdom that police are more forgiving of a driver speeding less than 10 mph over the limit appears to hold water.

A Houston Chronicle computer analysis of about 350,000 speeding tickets in the city of Houston over two years found that 99 percent were for going 10 mph or more over the limit.

Only in school zones were an appreciable number of tickets written for going less than 10 mph over the 20-mph limit. In those cases, about 3.4 percent of tickets were for driving 29 mph or less.

The finding was old news to police officers, who told the newspaper there were more than enough high-speed drivers to keep them busy. State law says the speed limit is whatever is "reasonable and prudent."

The roads on which police catch the highest percentage of speeders going at least 20 mph over the limit are the lower-speed freeways, with limits of 55 mph to 60 mph.

Drivers going 10 mph to 14 mph over the limit account for 70 percent of all speeding tickets on every type of road.