Was it the economy? The high cost of parking? Better bus service? City officials aren't sure, but they're pleased by a significant drop in the number of people driving solo to work to downtown Bellevue and Factoria.

The percentage of people driving alone to downtown dropped to 61 percent, compared with 71 percent in 2005, according to a survey commissioned by the City of Bellevue.

Factoria also registered a double-digit decrease,. Solo commutes dropped from 79 percent to 69 percent. However, the percentage of people driving alone to work was up slightly in the Crossroads and Bel-Red/Northup areas of the city.

The city is pushing alternative ways of getting to work because employment in downtown Bellevue is expected to jump from about 40,000 workers today to 63,000 in 2020.

According to the city, downtown commutes by bus bumped up to 19 percent last year, from 14 percent in 2005; and carpool commutes rose to 11 percent, from 10 percent. Commuting by other modes -- including vanpool, walking, biking and telecommuting -- each accounted for 3 percent or less.