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Definition
| the Manual on Uniform Traffic Control Devices |
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Definition
| Quantitative measure of quality of traffic flow |
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| the measure of effectiveness for determining LOS of freeway facilities |
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| Factor that relates the daily traffic volumes to the design hourly volume |
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| Peak Hour Factor (PHF) equation |
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Definition
PHF = hourly volume / (4*Peak 15 minute volume) |
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| Directional Distributions (D) |
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Definition
| Accounts for the differences in traffic flow by direction (assume 50/50 split unless known) |
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| Directional Design Hourly Volume (DDHV) equation |
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Definition
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Definition
| Divided highway with full control of access and 2+ lanes in each direction |
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Definition
| Outside the influence area of ramps and weaving sections |
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Definition
| Maximum sustained 15-minute flow rate (pcphpl) that can be accommodated by uniform freeway segment under prevailing traffic and roadway conditions in one direction of flow. |
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| 6 Steps in Basic Free Methodology |
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Definition
Step 1: Input Data
Step 2: Determine FFS
Step 3: Select FFS curve
Step 4: Adjust Demand Volume
Step 5: Estimate Speed and Density
Step 6: Determine LOS |
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Term
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Definition
Measure if flow is less than 1,000 pc/h/ln
Estimate if field of measure not possible |
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Definition
| Point after which estimated operating speed of freeway is less than FFS |
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Term
| To be effective, a traffic control device must: |
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Definition
Fulfill a need
Command attention
Convey a clear and simple meaning
Command the respect of road users
Give adequate time for proper response
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Term
| Five factors engineers should ocnsider for traffic control |
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Definition
| design, placement, operation, maintenance, uniformity |
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| Function of traffic signs |
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Definition
| Regulate, warn, guide, and inform |
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Definition
| Required, mandatory, or specifically prohibited (shall) |
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Definition
| Recommended but not mandatory (should) |
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Definition
| Permissive condition (may) |
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| Engineering study to ensure advantages outweigh disadvantages of traffic control |
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| MUTCD code for a stop sign |
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Definition
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Definition
| Part of signal cycle where no indication changes |
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Definition
| Part of the cycle allocated to traffic including the green, yellow, and all red intervals |
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Definition
| Left turns go second (thru traffic frist) |
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Definition
| One direction at a time (north thru and left go then south thru and left go) |
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Definition
| Phase sequence and interval length are not dependent on real time traffic (no detection) |
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Definition
| Some detection of some movements. Some phases may be called or skipped. |
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Definition
| All approaches have detection and all phases may be called or skipped |
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Definition
| Maximum flowrate for an approach assuming the light is always green |
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Definition
| Start up lost time, clearance lost time, total lost time (sum) |
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Definition
| Inefficiency at end of each phase due to stopping traffic |
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Definition
| The time when vehicles are moving through the intersection |
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Term
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Definition
| Capacity for a movement is a function of saturation flow rate, effective green, and cycle length |
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Definition
| The sum of the critical v/s ratios |
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Definition
| Cycle length that minimizes overall delay |
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Definition
| Movement in a particular phase that controls the timing of that phase |
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| Types of transportation plans |
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Definition
1. Long range transportation plans
2. Transportatin improvement program
3. Major investment and corridor plans
4. Project development plans |
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Term
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Definition
Home-based work (HBW)
Home-based other (HBO)
Non-home based (NHB) |
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Definition
| process by which the zone's productions and attractions are estimated |
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Definition
Process by which trips generated in one zone are allocated to other zones.
Use of gravity model to linkn productions and attractions into trips for every zone pair. |
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Definition
Use of utility theory based probability models for estimate percentage of trips by available modes for each zone pair.
Process to determine the number of trips between zones made by a particular mode |
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Definition
| Use of quilibrium theory to allocate trips to network routes |
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Definition
| Home based end of a trip or the origin of a non-home based trip |
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Definition
| Values adjusted during trip distribution to achieve convergence of the gravity model |
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Definition
| Factor that accounts for the distance between zones for trip distribution |
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| TAZ (traffic analysis zones) |
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Definition
| Unit for modeling based on census track boundaries and characteristics of the land use |
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| Maximum volume on a facility where you can still field measure the free flow speed |
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Definition
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| Four steps of the modeling process |
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Definition
1. Trip generation
2. Trip distribution
3. Mode and distribution choice
4. Route choice |
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| Output of the four step modeling process |
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Definition
| Number of trips made on a particular link |
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| Route performance function |
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Definition
| Equation describing the relationship between travel times and link volumes |
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Definition
| Model that uses the relative utility of a mode compared to utilities of all modes |
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