Not so fast: Bolte Bridge anomaly gives drivers false speed limit joy

Motorists were rejoicing over a new speed limit at the Bolte Bridge this morning.

But the celebrations were short-lived.

Ross and John were this morning swamped with calls from elated drivers who noted the speed limit on the Tullamarine Freeway was set to 100km/h in both directions between Dynon Road and Bulla Road.

Click PLAY to hear their reactions

That section of road and the Bolte Bridge itself has featured an 80km/h speed limit in recent years, frustrating drivers when the freeway had seemed suited to a 100km/h speed limit, as it had been in recent years.

But the speed limits switched back to 80km/h later in the morning.

The Department of Transport later told Ross and John the change was an anomaly caused by the freeway’s variable speed limit algorithm.

“We’ve got sensors in the road that analyse the traffic volumes, the density of the traffic … and whether there’s any moisture on the road,” the transport department’s Chris Miller said.

“When the conditions are perfect, the speed limit goes up to 100km/h.”

Click PLAY to hear more from Chris Miller

Caller Mark says yep, still 100km on the Bolte, and back to 80km/h when you get to the DFO at Bulla Rd.

— 3AW Breakfast (@RossAndJohn) December 4, 2019