Old article, but still interesting...
Gridlocked
GTA ECONOMY DINGED BY EVERY CRASH ON THE 401 - NORTH AMERICA'S BUSIEST FREEWAY
By BRIAN GRAY, TORONTO SUN
Ready ... set ... GO?
Waiting the hardest part
No Easy Way Out
THE "PHENOMENAL" number of vehicles on Hwy. 401 as it cuts through Toronto makes it the busiest freeway in North America -- and each collision can cost Ontario's economy thousands of dollars. Traffic on the 401 has doubled in the past 25 years and now averages 410,000 cars an hour, said Phil Masters, the head of the province's advance traffic management centre, commonly known as the Compass system that monitors traffic throughout the GTA.
"Hwy. 401 is definitely the most heavily travelled freeway in North America, probably the most heavily travelled freeway in the world," Masters said. "We're up close to 500,000 on peak days, which is just a phenomenal number."
That staggering figure compares with 380,000 on Los Angeles' famed freeways and 350,000 on the I-75 in Atlanta.
The huge volume has also changed the job of the officers who police it, said Sgt. Cam Woolley of the Ontario Provincial Police, which investigates 15,000 collisions a year on the 401 in the Toronto area.
"Collisions have gone from being merely inconvenient to a severe danger for police, drivers and the factories that now rely on the goods being shipped on the road," Woolley said.
He said a four-hour closure of three or more lanes can hamper businesses waiting for inventory to be delivered.
Lanes used to be shut down for eight to 14 hours while investigators did their job. Now, with heavier tow trucks, damaged cars and trucks can be removed and lanes re-opened quicker. A complete towing cleanup can cost as much as $30,000, Woolley said.
"Hundreds have been injured and many killed over the years in secondary collisions," he said.
Overhead message boards, introduced in 1991, have cut down on secondary collisions by at least 12%, Masters said.