I-66 Multimodal Study Final Report - Virginia Department of ...

Multimodal PackagesDynamic Merge (Junction Control) – As defined by the FHWA, this is a method to dynamicallychange lane allocation at an interchange. It can be used at freeway off-ramps or on-ramps;particularly for high-volume ramps often associated with major freeway-to-freewayinterchanges. This treatment is being implemented as part of the ATM at the junction ofVA-267 and I-66 eastbound.Junction control would be used to “close” the right lane of the mainline upstream of the rampthrough the use of lane-control signs in order to give ramp traffic a near free-flow onto themainline. Junction control provides priority to the facility with the higher volume and allows alane drop to the lesser volume roadway. In addition to improving the flow conditions on theramp, it could improve safety, as the hesitation of ramp drivers looking for gaps increases thepropensity of rear-end collisions. The final cost of implementing this treatment, includinginstallation of gantries, lane-control signs, and software integration is undetermined. Annualoperations and maintenance costs are estimated at approximately 10 percent of the estimatedcapital costs.Outside the BeltwayThe following treatments will be implemented outside the Beltway as part of the ATM:Speed Management – Speed advisories are provided based on observed traffic conditions;Queue Warning – Dynamic message signs inform travelers of approaching queues/bottlenecks;and;Hard Shoulder Running – Lane-control signs manage the use of shoulders as a travel lane.Additional ICM StrategiesTo expand the Active Traffic Management (ATM) to a fully integrated corridor managementstrategy for I-66, the following improvements could be implemented:Speed Harmonization – Although not included in the I-66 ATM project inside the Beltway,speed harmonization is a possible strategy for use in this segment of I-66, particularly undermanaged lane scenarios. Speed harmonization systems use changeable speed limit signsposted over each lane to regulate freeway speeds based on prevailing traffic conditions.This strategy can be used:To control traffic speeds during adverse weather conditions as a safety measure;When there is an incident or congestion on specific segments in order to reduce the chancesof secondary accidents and facilitate a smoother flow of traffic; andTo improve the overall efficiency of a freeway network.The I-66 corridor is potentially a good candidate for this strategy, given the numerous locationsalong the corridor with heavy traffic merges.3-64 I-66 Multimodal Study