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From page 37... ... 37 C h a p t e r 3 This chapter identifies technologies and non-lane-widening treatments that improve network capacity and reduce the breakdown probability on arterial and freeway facilities and networks. The first section focuses on technologies, both emerging and visionary, that have the ability to positively impact overall network operations. Read the entire page →
From page 38... ... 38 centralized network management system could also act as the recipient and processor of data sent from individual vehicles. This scenario would require a management system capable of effectively interpreting and distributing the appropriate data, as well as a long-distance communication channel such as a satellite-based system or high-capacity wireless network. Read the entire page →
From page 39... ... 39 Table 3.3. Communications Matrix Technology Matrix To From Vehicle Infrastructure Local Control Network Control Vehicle VV1 Receive Nearby Vehicle Decisions IV1 Infrastructure Status LV1 In-Vehicle Display of Signals NV1 Route Guidance VV2 Transmit Subject Vehicle Decisions IV2 In-Car Speed Limit Adjustment Display LV2 Reversible Lane Control NV2 Network Highway Advisory Radio VV3 Collaborative All-Way Stop Control IV3 Local Conditions via Advisory Radio LV3 In-Vehicle Lane Assignment Display NV3 511 Assistance VV4 Collaborative Gap Acceptance IV4 Smart Work Zone Navigation LV4 NV4 External Vehicle Speed Control VV5 Adaptive Cruise Control IV5 Automated Parking Enforcement LV5 NV5 VV6 Collaborative Driving System IV6 Intelligent Vehicle and Highway System LV6 NV6 VV7 IV7 LV7 NV7 VV8 IV8 LV8 NV8 Infrastructure VI1 Vehicle Dynamics Info II1 Advance Incident Detection/Warning LI1 Dynamic Advance Warning Signals NI1 Capacity Assignment Decisions VI2 Weather/Road Conditions II2 Congestion Detection/ Warning LI2 NI2 Weather Forecasts VI3 Electronic Toll Collection II3 LI3 NI3 Dynamic Congestion Tolling VI4 II4 LI4 NI4 VI5 II5 LI5 NI5 VI6 II6 LI6 NI6 VI7 II7 LI7 NI7 VI8 II8 LI8 NI8 Local Control VL1 Approach Trajectory Input IL1 Intersection Conditions LL1 Signal Coordination NL1 Control Coordination VL2 Turning Movement Options IL2 Dynamic Speed Limits LL2 NL2 Oversaturated Control VL3 Lane Use Options IL3 Blocked Lane Information LL3 NL3 Network-Level Ramp Metering VL4 IL4 Ramp Meter Override LL4 NL4 Flow Management VL5 IL5 Sensor Status LL5 NL5 Plus Lane VL6 IL6 LL6 NL6 Algorithms for Speed Adjustment VL7 IL7 LL7 NL7 VL8 IL8 LL8 NL8 Network Control VN1 Probe Information (AVI, AVL) Read the entire page →
From page 40... ... 40 As a result, two technologies with similar objectives actually have very different pathways for implementation, as well as very dissimilar methods of combining with other technologies. The following provides a summary of the technologies listed in Table 3.3 and sorted by each of the four origin entities discussed below. Read the entire page →
From page 41... ... 41 or safe speed limits displayed on digital overhead signs based on current weather conditions. IL4 Ramp Meter Override systems will also prove necessary within-ramp metering schemes to prevent arterial backups. Read the entire page →
From page 42... ... 42 To local conTrol Network control over local control devices will likely emerge in a number of different ways, each intended to use real-time information processed at a central network agency to dynamically adjust traffic flow. NL3 Network-Level Ramp Metering and NL2 Oversaturated Control, where a network system completely overrides all signals in a region to flush an arterial network, are both powerful examples of this practice. Read the entire page →
From page 43... ... 43 Table 3.4. Ranked Technology Options Ref Technology Details Timetable (1  test bed; 2  selective; 3  widespread) Read the entire page →
From page 44... ... 44Table 3.4. Ranked Technology Options (continued) Read the entire page →
From page 45... ... 45 Table 3.4. Ranked Technology Options (continued) Read the entire page →
From page 46... ... 46 The next 17 technologies will take slightly longer to achieve widespread availability (2) and have a few, but not an overwhelming number of, barriers to implementation (2) Read the entire page →
From page 47... ... 47 Table 3.5. Summary of Treatments for Achieving Improvements in Network Operations Treatment Freeway Arterial Increases Capacity Decreases Probability of Breakdown Increases Capacity Decreases Probability of Breakdown Operational Treatments Lane Treatments - Narrow lanes - Reversible lanes - HOV lanes - Variable lanes - On-street parking restrictions • • • • Signal Timing - Signal retiming - Adaptive traffic control - Queue management - Transit/truck signal priority • • Traffic Demand Metering - Ramp metering - Mainline metering - Ramp closures - Arterial demand metering • • Congestion Pricing - Pre-set pricing - Dynamic pricing - Distance/vehicle class tolls - High-occupancy tolls - Central area pricing • • Traveler Information - Pretrip information - In-vehicle information - Roadside messages - GPS navigation devices • • Variable Speed Limits • • Design Treatments Access Management - Raised medians - Access consolidation/relocation - Right turn channelization - Frontage roads • • Geometric Design Treatments - Flyovers - Improving weaving sections - Alternate left turn treatments - Interchange modifications - Alignment changes • • • • Truck-Related Treatments Truck/Heavy Vehicle Treatments - Truck-only lanes - Truck restrictions/prohibitions - Truck climbing lanes • • • • Read the entire page →
From page 48... ... 48 adding lanes at off-ramps to mitigate the impact of a downstream signal on the surface street of an interchange, and adding temporary (median) lanes at weaving sections during peak periods. Read the entire page →
From page 49... ... 49 One special application of ramp metering is the closure of one or more on-ramps during congested peak periods. In effect, this action does not increase demand on the downstream freeway section, but does require a high level of user information and signing to divert vehicles from the on-ramp to the adjacent arterial system. Read the entire page →
From page 50... ... 50 by VMSs. This application contributes to a more patient behavior in case of congestion and a less nervous style of driving in flowing traffic. Read the entire page →
From page 51... ... 51 Truck/Heavy Vehicle Restrictions The management of truck traffic can have a positive impact on traffic operations for both freeways and arterial facilities. Traffic operations improvements relating to trucks and to capacity and sustained service rates may require additional factors to be considered such as allowable delivery schedules, weight restrictions on arterial streets, and vertical clearance limits. Read the entire page →

From page 37...

... 37 C h a p t e r 3 This chapter identifies technologies and non-lane-widening treatments that improve network capacity and reduce the breakdown probability on arterial and freeway facilities and networks. The first section focuses on technologies, both emerging and visionary, that have the ability to positively impact overall network operations.