By JOHN AGUILAR, The Denver Post
DENVER (AP) – Alleviating the notorious rush-hour traffic jams on Interstate 25 south of Denver will require controlling the access of thousands of motorists to the freeway with unprecedented split-second precision previously in Colorado.
That is why, over the next few weeks, state transportation officials will be launching the Smart 25 Managed Freeway pilot program, using what is known as a “coordinated ramp counter” on a stretch of 14. miles from I-25 northbound between University Boulevard in Denver and Ridgegate Parkway in Lone. Tree.
Many ramps on Denver’s subway freeways have traffic lights to control traffic, but they are not programmed to respond to conditions in real time. By constantly and carefully modifying the length of time that cars wait on ramps before joining the freeway, traffic engineers believe that slowdowns and traffic jams can be drastically reduced, if not avoided.
The proof, according to Zach Miller, director of the Smart 25 project at the Colorado Department of Transportation, lies nearly 8,800 miles from Melbourne, Australia.
“Australia has figured out how to use algorithms to solve complex traffic problems to avoid traffic jams,” Miller said. “I hope this technique can also be of benefit to the CDOT.”
What Australia’s second-largest city discovered after implementing its coordinated ramp counting program on a stretch of the M1 motorway ten years ago is impressive: The number of passing vehicles has increased by 25 % during peak periods, travel speeds improved by 35% to 60% during peaks and crashes decreased by 20 to 50%.
“We can’t control what drivers do, but we can control the environment in which they make those decisions,” said Matt Hall, director of the Victoria Department of Transportation.
And this environment is extremely precise: the traffic conditions on the roadway are constantly monitored by sensors, which send data to computers using algorithms. The duration of the green or red light on an access ramp is adjusted every 20 seconds.
“It is slowly pushing back red weather as needed,” said John Gaffney, strategic advisor at the Victoria Department of Transportation. “And if one area is in trouble, we share the pain throughout the system. “
Sometimes that means adding only a tenth of a second to motorists’ wait times, Gaffney said, but manipulating wait times on many ramps for miles of freeway helps fill in the gaps on the highway to keep traffic flowing. It only takes two more vehicles per kilometer of track to get it all bogged down, he said.
The stretch of I-25 through the Denver Tech Center sees an average of more than 250,000 vehicles per day, according to CDOT data. Melanie Ward, Centennial’s strategic advisor for transportation and mobility, said city residents have no shortage of complaints about I-25.
“Our residents tell us all the time that traffic congestion is the biggest concern,” she said.
She welcomes CDOT’s Smart 25 pilot program as a potential solution to congestion – and perhaps helping reduce the metropolitan area’s ozone alert days – but fears the prolonged red limelight could signify backups in the streets of connection.
“We want to make sure that we don’t see I-25 improvements at the expense of local roads,” Ward said.
In Melbourne, Gaffney said, that hasn’t been a problem. If a ramp starts to get overloaded, cars will be released while the system transfers wait times somewhere on the road to compensate.
“You have to have all the ramps looking at the system,” he said.
Hall and Gaffney both said Colorado is at the forefront of implementing a coordinated ramp measurement system. Utah, Georgia, North Carolina, and Tennessee, among other states, have considered using it, but the I-25 already has much of the infrastructure needed.
This includes the sensors on the freeway and a dozen “detection pucks” at each of the 18 ramps involved in the study, Miller said. The first three months of the pilot, which could start as early as the end of June, will be devoted to data collection.
The next two months will be a “soft start” of the program, followed by four months of full operation. Miller said the CDOT is spending $ 5 million on the pilot program and will be able to assess next year whether this is something to be implemented on a permanent basis.
“This hallway was completely renovated 15 years ago,” Miller said, referring to the additional lanes built on I-25 and I-225 in 2006 as part of the $ 800 million T-REX project. “However, most of the improved capacity gains have been lost due to increased demand.”
Jeremy Hanak, Director of Public Works for Greenwood Village, just wishes the worst rush hour rush through his town didn’t develop any more or more intense than it is.
“If you get a coordinated traffic light system, you can increase efficiency,” Hanak said. “I hope you can keep yourself from going from a one hour peak to a two hour peak.”
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