The toll for a solo driv­er along the In­ter­state 66 cor­ri­dor hit $46.75 dur­ing the Wednes­day morn­ing rush, ap­proach­ing a record high.

On Feb. 28, the toll along the east­bound stretch of I-66 hit $47.50.

The tolls are paid by driv­ers who choose to ride alone and are based on a dy­nam­ic pric­ing sys­tem, which chan­ges the rate every six min­utes, based on speed and traf­fic vol­umes.

Many driv­ers — and some poli­ti­cians — have com­plained a­bout the fluc­tu­at­ing and high toll rates. The toll runs along 10 miles of I-66 in­side the Beltway in Northern Vir­ginia. Car­pool and pub­lic trans­por­ta­tion vehi­cles don't pay the toll.

A spokeswoman for the Virginia Department of Transportation said Wednesday morning that traffic experts were looking more into what was causing the spike in toll rates but that it may not be any one thing in particular -- just simple volume. Typically, trans­por­ta­tion of­fi­cials have said the high tolls re­flect the con­gested traf­fic con­di­tions on oth­er area road­ways.

On Wednesday morning around 8:30 a.m., there were no major accidents on area roads in Northern Virginia, but there was heavy traffic along roads around Ballston and along the highway coming into the District and along the Theodore Roosevelt bridge.