All we have to fear.

In "9/11's Fatal Road Toll: Terror attacks presaged rise in U.S. car deaths" (SN: 1/17/04, p. 37), it was assumed that people who switched from planes to cars after the terrorist attacks did so because of fear. However, many people who switched probably did so because of the inconvenience of added airport security. But before these extra deaths can be blamed on fear, security, or something else, it is necessary to determine why people switched.

BOBBY BAUM, BETHESDA, MD.

I wonder if anyone's checked speeding tickets for the period considered. As someone who hates airport lines at the best of times, I decided to drive from my home in northeastern Pennsylvania to a business appointment in Boston in late October 2001. On the Massachusetts Turnpike, I clocked the average speed at between 80 and 85 miles per hour, which I initially attributed to crazy New England drivers. However, over the next months, I noticed that on almost all highways people were driving, on average, about 10 mph faster than previously. Did it have to do simply with more people on the road trying to make up for lost flying time? Or did it reflect a heightened fear?

DEREK DAVIS, DUSHORE, PA.

For some, driving instead of flying may have been due to fear of dying in a hijacked plane. At least as common are folks like me, who feel no need to subject themselves to the harassment of someone pawing through your carry-on or getting patted down.

MICHAEL SAKARIAS, JUNEAU, ALASKA