Term
| 3 Levels hierarchy of intersections |
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Definition
-no control
-yield or stop
-traffic signal |
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Term
| How many cars can a 4 way stop handle? |
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Definition
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Term
| CMA- and where it came from? |
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Definition
-Critical Movement Analysis
-came from questions/complaints about HCM |
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Term
| 2 factors that affect 3 levels of control |
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Definition
-Can you see?? (visibility)
-Volume |
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Term
| Downside of traffic signal |
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Definition
| Pressure on the Traffic Engineer to time it correctly |
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Term
| 3 Main things that have warrants |
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Definition
-stop signs
-traffic signals
-left turn lanes |
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Term
| With what do you coordinate signals? |
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Definition
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Term
| What is required to coordinate multiple signals? |
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Definition
| -the same cycle length (to maintain repeatability) |
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Term
| "Barnes Dance" - Henry Barnes |
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Definition
-A signal that has a N-S phase, E-W phase, and an exclusive pedestrian phase
-short lived bc not very efficient- peds can still walk one way no matter which phase |
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Term
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Definition
-highest volume in N-S
-highest volume in E-W
-then take percentages (divide by 4 lane total) |
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Term
| 2 ways you can help people at an intersection |
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Definition
-markings
-channelization |
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Term
| 3 requirements for signal faces |
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Definition
-minimum of 2 faces should be visible to each primary movement (in case one goes out)
-faces placed within 20 deg angle around centerline
-all faces are placed at mounting heights from MUTCD Standards |
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Term
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Definition
-span wire
-post
-mast arm |
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Term
| Purpose of the backing on a traffic signal |
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Definition
| -to help with sight problems from the sun |
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Term
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Definition
RTOR = Right turn on red
the advantage is more productivity |
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Term
| 3 Fundamentals of signal timing and design |
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Definition
1. safe and effective phase plan
2. determine vehicular signal needs
3. determine pedestrian signal needs |
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Term
| change and clearance interval |
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Definition
change = yellow
clearance = all red |
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Term
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Definition
| Walk, Flashing Don't Walk, & Don't Walk |
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Term
| 2 types of Actuated Control |
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Definition
semi-actuated- used where a small side street intersects with a major arterial (less capacity on sidestreets)
full actuated- all lanes of all approaches are monitored by detectors (more equal capacity in both directions) |
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Term
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Definition
-means change in capacity (delta C)
-Basically the same as full actuated control with demand response features
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Term
Types of detectors (inductive loop)
How far away is a detector from a stopline? |
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Definition
-point detection (passage)
-presence detection (area)
-2 feet |
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Term
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Definition
| Passenger Car Equivalents (Passenger Car Units) |
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Term
| 3 Things a T.E. can do if critical lane can't handle capacity |
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Definition
-increase cycle length
-change the phase (generally adding protected left turn)
-Adding lanes |
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Term
| HCS- Where did it originate from? |
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Definition
Highway Capacity Software
-originated from U of Florida |
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Term
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Definition
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Term
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Definition
-critical lane group
-v/s ratio (demand)
-capacity and saturation flow rate
-LOS
- effective green time (g) |
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Term
| Calibrating Adjustment Factors |
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Definition
-adding lanes
-decrease demand (traffic)
-optimum phase |
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Term
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Definition
| Intelligent Vehicle Highway Systems -> Intelligent Transportation Systems |
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Term
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Definition
-ABS
-GPS
-Side/Front Airbags
-Cruise Control
-TMC (traffic management centers) |
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Term
| Examples of congestion pricing |
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Definition
-short term vs. long term parking
-commuters - toll bridges
-parking meters
-Central Business District |
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Term
| Bottom line is the driver! % of accidents that are drivers fault? |
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Definition
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Term
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Definition
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Term
| Good bandwidth efficiency = |
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Definition
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Term
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Definition
-simple progression
-forward progression
-flexible progression
-reverse progression
-alternate progression |
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Term
| undersaturated vs. oversaturated |
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Definition
undersat - v/c < 1
oversat - v/c >= 1 |
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Term
| When networks are congested, 3 objectives |
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Definition
-maximize throughput
-utilize storage
-equitable service |
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Term
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Definition
| going back to a phase more than once in a cycle |
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Term
| 4 classifications of congestion |
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Definition
light
moderate
heavy
oversaturated |
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Term
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Definition
internal
external
release |
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Term
| remedy for oversaturation |
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Definition
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Term
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Definition
difference between the time when the upstream intesection turns green and the downstream intersection turns green
ex t2 - t1 |
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Term
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Definition
| difference between the first vehicle that can pass through the entire system without stopping and the last vehicle that can pass through without stopping (seconds) |
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