10.3.4.4 Results and Measure of Effectiveness (MOEs)
Intersection analysis using HCM-based tools (i.e., Synchro and HCS) are evaluated in terms of LOS based on either control delay, LOS score (a measure used to rank pedestrian and bicycle facilities based on pedestrian perception and bicycle perception), or experienced travel time (ETT). shows the MOEs for each type of operational analysis tool. Enhanced operational performance equates to a low v/c ratio, low control delay, LOS A (optimal) to LOS D (acceptable), and short queue length.
The delay output by Vissim is calculated using a different method than in HCM based tools, so use caution when comparing the delays between Vissim results and HCM-based software. Relevant pairs of intersection chapters from the HCM 7th Edition are listed below:
- Signalized Intersections: Chapter 19 (methodology), Chapter 31 (applications);
- Two-way Stop-controlled Intersections: Chapter 20 (methodology), Chapter 32 (applications);
- AWSC: Chapter 21 (methodology), Chapter 32 (applications);
- Roundabouts: Chapter 22 (methodology), Chapter 33 (applications); and
- Alternative Intersections (Continuous Flow/Displaced Left-Turn, RCUT, MUT): Chapter 23 (methodology), Chapter 34 (applications)
shows HCM LOS criteria for signalized intersections. provides HCM LOS criteria for TWSC and AWSC intersections.
Tool | Outputs |
---|---|
CAP-X | v/c ratios of top 10 selected intersection types |
Synchro | v/c ratio, control delay, LOS, 95% queue length |
HCS | v/c ratio, control delay, LOS, 95% queue length, |
Warrants (using Synchro, HCS, or other tools) | Warrant met or warrant not met |
Vissim | Average vehicle travel times (sec), average total delay per vehicle (sec), percent of queue length, ETT |
CORSIM | Control delay, queue length, travel speed, travel time, LOS |
Control Delay (s/veh) | LOS by Volume-to-Capacity Ratioa | |
---|---|---|
v/c ≤ 1.0 | v/c >1.0 | |
≤ 10 | A | F |
> 10-20 | B | F |
> 20-35 | C | F |
> 35-55 | D | F |
> 55-80 | E | F |
>80 | F | F |
Note: For approach-based and intersection-wide assessments, LOS is defined solely by control delay.
Control Delay (s/veh) | LOS by Volume-to-Capacity Ratio | |
---|---|---|
v/c ≤ 1.0 | v/c >1.0 | |
≤ 10 | A | F |
> 10-15 | B | F |
> 15-25 | C | F |
> 25-35 | D | F |
> 35-50 | E | F |
>50 | F | F |
Note: The LOS criteria apply to each lane on a given approach and to each approach on the minor street. LOS is not calculated for major-street approaches or for the intersection.