The Illinois Department of Transportation (IDOT) was busy Monday setting up a Smart Traffic Monitoring (STM) system to help motorist navigate the construction zone on the bridges that carry Interstate 55 over the Des Plaines River, trying to keep what happened last year from repeating this year.
The construction project officially resumed March 21 with long-term lane closures expected within the next couple days, according to the Illinois Department of Transportation.
The bridge rehabilitation project for the southbound lanes got a late start last year - crews weren't on site until after July 4. The traffic backups were often very long - sometimes the northbound lanes were snarled as far south as Route 113, and the southbound drivers hit the brakes at Interstate 80.
Those backups often resulted in crashes; 143 of them through mid-October 2013, including two fatal incidents. Emergency responders took 60 patients to Joliet hospitals.
At the urging of State Rep. Larry Walsh Jr.'s Blue Ribbon Panel studying the issue, this year, IDOT will employ STM technology to better inform motorists about the conditions in the work zone, in time to take a detour if necessary.
Project manager Mike Wiater said drivers will see changeable message signs that look like the signs that have been on the side of the road the last couple of weeks. They are different, because they're linked into the STM system provider's network.
What drivers may not notice are the small trailers carrying sensors that are an integral part of the system. The sensors use Doppler radar and microwave technology to take readings of the two-minute average speed of the vehicles passing them. The sensors are already in use on I-80.
The sensor data is used by the system software to analyze the movement of traffic, to decide whether traffic is delayed; and if it is, how much it is delayed.
"Based on that, we can start putting different message on the signs," Wiater said. For example, when traffic is moving above 35 mph, the signs will warn of a delay ahead. Below 35 the message boards will read "slow traffic ahead," and below 25 the message will be "stopped traffic ahead." As traffic builds, the signs will change with appropriate messages for motorists. The process is fully automated and messages are changed in real time.
There are five signs for the southbound lanes and four for the northbound, placed strategically up to 25 miles in advance of the workzone. IDOT will be able to use the system to tell drivers the travel time through the workzone and suggest taking the alternate.
IDOT has limited opportunities for the signage to work as well on the northbound lanes, as it will on the southbound lanes, since the alternate is Route 47 and the link to Route 47 from the south is at Dwight.
"For the northbound trip, for people who are coming up from that far south and they get to Dwight, that sign, if we've got enough of a delay through the workzone, it's going to say, 'you should use the alternate.'"
The signs closer to the workzone will specify delay times, but more importantly, will warn of slow or stopped traffic ahead.
"When we had the trouble last year it was basically, vehicles running into the back end of the vehicle in front of it. So what we're trying to do with those close in ones is warn people that there's stopped traffic, be ready to stop," Wiater said.
There will also be traffic cameras, accessible to IDOT, so staff will be able to monitor how well traffic is flowing, and if there is an incident, will have an eye on the scene. IDOT is working with the vendor to see if those pictures can be shared with emergency responders.
Wiater expects the southbound lanes to close on Thursday. Workers will finish the repairs that weren't completed last year because the project started late and entailed replacement of structural steel.
Completion of repairs on the southbound lanes should take seven to 10 days. In mid- to late-April, barrier walls will be installed and all traffic will be shifted to the southbound structure to allow repairs on the northbound bridge.
IDOT got a jump start on the northbound project by doing a late-season inspection of the underside of the bridge. The structural steel pieces that inspection indicated need to be replaced are already being fabricated - the process that made the southbound project seem to move so slowly.
"There are individual pieces that, if you get down there and find that it's rusted out ... that piece has to be measured and detailed with drawings, then that has to go out to a fabrication shop that's got to find the piece of steel that's that thickness, that size and that length and that width, then do the fabrication, do the cutting and drill the holes, then that comes back to the site to get installed," Wiater said. "So that's what gets complicated."
If work crews run into just a handful of pieces they didn't anticipate replacing, it will take two to three weeks to have them fabricated.
The project is expected to be completed by Labor Day, including consideration for time for parts fabrication. The project length is comparable to that of the southbound lanes. The work includes structural steel repairs and painting; bridge deck patching and deck resurfacing on the northbound structure.
Illinois State Police will have extra troopers in the area 24 hours per day throughout the construction season. Troopers will enforce the Fatal Four violations; speeding, distracted driving, driving under the influence, and seatbelts. In addition, they will be monitoring and enforcing the hand-held cell phone ban. The new law bans hand-held cellphone use except in an emergency and allows only for speakerphones and headsets that feature voice-activated or one-digit dialing. The new law, which took effect Jan. 1, also imposes fines starting at $75 for drivers caught with phone in hand. Violators could pay $150 for repeat offenses and eventually have their driver's licenses suspended.
Last year, ISP wrote over 4,100 citations in the Des Plaines River bridge workzone. Additional manhours for enforcement have been allotted for the 2014 construction season.