Each day, about 3,900 vehicles fan out across Jacksonville on  behalf of the city’s government.

Police cars, bulldozers, fire trucks and code enforcement  officials — all moving, all burning fuel, all costing more to operate as gas  prices rise.

Still, despite the national average fuel price rising about 40  cents since the fiscal year began in October, the city fuel bill is still under  budget. It is projected to stay there, too, despite the near-certainty of even  more expensive summer gas and even though the city is not quite sure why its  consumption is down.

Jacksonville plans to spend about $26 million on fuel this  fiscal year, $3.4 million more than it did the previous fiscal year.