Transportation Management Plans: Striking a Balance Between Dozers and Delays
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In some ways, Caltrans sets for itself an almost impossible goal when undertaking construction projects: complete major improvements on some of the nation’s most congested freeways, but minimize the inconvenience to motorists. It’s the infrastructure equivalent of ripping a tablecloth off a dinner table without disturbing the dishes. Remarkably, in most cases, we come pretty close to executing this trick, albeit with some rattling of the flatware. That’s possible in large part due to an essential tool most motorists have never heard of: the transportation management plan, or TMP.
TMPs are basically a blueprint for minimizing traffic delays associated with lane closures and other planned activities on Caltrans freeways and highways. TMPs can be fairly simple for common operations, such as repairing guardrail, or extremely complex for projects with significant impacts, such as a full closure on high-volume freeway (think Carmageddon). They include some combination of strategies from six categories: public information (e.g., press releases), motorist information (e.g., changeable message signs), incident management (e.g., the Construction Zone Enhanced Enforcement Program, aka COZEEP), construction strategies (e.g., lane requirement charts), demand management (e.g., transit incentives), and alternate routes (e.g., retiming signals on nearby roads).
In District 7, TMPs are particularly important. Currently, there is over $2 billion in work underway in Los Angeles and Ventura counties, while at the same time, 100 million miles are traveled by motorists on our freeways and highways every day. The sheer volume of traffic in District 7 and resulting congestion mean that keeping everyone moving is more difficult here than anywhere else in California — and arguably in the nation. Add construction to the mix, and serious delays seem not only likely but inevitable.
Except that it’s not inevitable, thanks in large part to the unsung heroes in the Office of the District Traffic Manager (DTM), which includes a team of about 27 people. District 7 has three traffic management areas, each with its own area manager: Denis Katayama (South), Martin Oregel (North), and Albert Yu (West). The area managers and their staffs are the minds behind TMPs and the painstakingly detailed lane requirement charts and associated contract specifications contained therein.
District 7 is unique in that it also has a District Lane Closure Review Committee (DLCRC) required by a district directive (DD 21), underscoring the importance of high-level review of major closures. The DLCRC is made up of deputies who evaluate TMPs with significant closures — such as those involving a full closure of a major freeway — and make final decisions. In some cases, they may ask staff to gather additional information to justify closure strategies.
Such scrutiny is necessary because delays are one of the most common sources of complaints District 7 receives – from businesses, elected officials, commuters, residents, etc. Motorists, it turns out, do not like being inconvenienced, though they tend to be more forgiving when they understand the reason for closures and the extensive planning required to implement them, which is often a years-long process. The development of a TMP for a major construction project begins during project initiation and planning.
“We don’t have a lot of information at that stage, but that’s when it begins,” said Katayama. “Once the project gets to design, more information comes in, and then in construction, we’re constantly modifying the TMP because things are so dynamic. We do our best, but we can’t anticipate everything.”
For example, traffic patterns resulting from a detour might indicate that signals should be retimed on a nearby surface street, or additional portable changeable message signs (PCMS) may be needed, or a lane closure might need to be picked up earlier. Finding ways to reduce delays is as much art as science, requiring a creative intellect and an intuitive sense of traffic behavior.
“TMPs are very subjective. There’s no one way to do things,” said Katayama. “Every project is different. No TMP is the same, and that’s what makes it interesting.”
Essentially, TMPs are an ever-evolving balancing act. Caltrans must minimize delays while at the same time providing contractors with an adequate work window. As peak hours begin earlier in the morning and end later at night, striking that balance becomes increasingly difficult. Contractors would love to shut down an entire freeway from 8 p.m. to 8 a.m. and lay miles of slabs in one fell swoop. That, of course, would leave motorists seething and dialing up their elected officials. To avoid this scenario, a contractor might be given three lanes to work with between midnight and 7 a.m. on the weekend, while motorists get a lane or two squeeze by. It’s not perfect, but it’s a workable compromise.
In the 13 years since Caltrans began requiring TMPs, we’ve learned a number of valuable lessons. One is that TMPs do significantly reduce delays — so says Federal Highway Administration studies examining Caltrans’ use of TMPs. Another is that of the six TMP strategy categories, the most effective is good public outreach that encourages motorists to avoid the impacted area entirely. Additionally, maintaining close coordination with local agencies on detours and signal timing is crucial. Also, sometimes it makes more sense to use extended closures or full closures rather than numerous night closures — the sometimes being cases in which there’s no other way to complete the work, such as when demolishing an overcrossing.
DTM staff continue to improve their TMP strategies, develop new techniques, and experiment with new tools, such as Automated Work Zone Information Systems (AWIS). AWIS uses advanced computer technology and wireless sensors to collect and process traffic data to provide motorists with real-time information on PCMSs upstream of the construction zone.
For example, if a closure is causing traffic speeds to drop, the upstream PCMS might read, “Slow Traffic Ahead.” The signs could also encourage motorists to use another route. A scaled-down version of AWIS, which had web browser-controlled PCMSs but no traffic sensors, was used successfully on Summer Slam on SR-60 this past July and August, and DTM staff are looking forward to using a more robust version of the technology in the future.
The beauty of AWIS is that it transfers traffic monitoring duties to a computer program that also controls PCMS content, freeing up DTM staff for more complex tasks. AWIS also improves work zone safety because fewer Caltrans employees are exposed to live traffic. And by providing motorists with relevant real-time traffic information, we can reduce incidents and complaints.
“This is the future,” said Katayama. “It’s all automated. We set it up, but we don’t have to be there.”
Traffic management staff may not be physically there, but their imprint is all over every successful closure. At core, the most important part of every TMP isn’t the high-tech tools and strategies detailed within — it’s the experience, insights and creativity of the people who develop them.