# Shared Flashcard Set

## Details

Traffic Engineering Test #2
TE Test #2
42
Engineering
11/01/2010

## Additional Engineering Flashcards

Term
 3 Levels hierarchy of intersections
Definition
 -no control -yield or stop -traffic signal
Term
 How many cars can a 4 way stop handle?
Definition
 1600 vph
Term
 CMA- and where it came from?
Definition
 -Critical Movement Analysis -came from questions/complaints about HCM
Term
 2 factors that affect 3 levels of control
Definition
 -Can you see?? (visibility) -Volume
Term
 Downside of traffic signal
Definition
 Pressure on the Traffic Engineer to time it correctly
Term
 3 Main things that have warrants
Definition
 -stop signs -traffic signals -left turn lanes
Term
 With what do you coordinate signals?
Definition
 Time-space diagram
Term
 What is required to coordinate multiple signals?
Definition
 -the same cycle length (to maintain repeatability)
Term
 "Barnes Dance" - Henry Barnes
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
Term
 Critical lane volumes
Definition
 -highest volume in N-S -highest volume in E-W -then take percentages (divide by 4 lane total)
Term
 2 ways you can help people at an intersection
Definition
 -markings -channelization
Term
 3 requirements for signal faces
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
Term
 3 ways to mount signals
Definition
 -span wire -post -mast arm
Term
 Purpose of the backing on a traffic signal
Definition
 -to help with sight problems from the sun
Term
Definition
 RTOR = Right turn on red the advantage is more productivity
Term
 3 Fundamentals of signal timing and design
Definition
 1. safe and effective phase plan 2. determine vehicular signal needs 3. determine pedestrian signal needs
Term
 change and clearance interval
Definition
 change = yellow clearance = all red
Term
 The 3 pedestrian signals
Definition
 Walk, Flashing Don't Walk, & Don't Walk
Term
 2 types of Actuated Control
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)
Term
 Volume-Density Control
Definition
 -means change in capacity (delta C) -Basically the same as full actuated control with demand response features
Term
 Types of detectors (inductive loop)   How far away is a detector from a stopline?
Definition
 -point detection (passage) -presence detection (area)   -2 feet
Term
 PCE (aka PCU)
Definition
 Passenger Car Equivalents (Passenger Car Units)
Term
 3 Things a T.E. can do if critical lane can't handle capacity
Definition
 -increase cycle length -change the phase (generally adding protected left turn) -Adding lanes
Term
 HCS- Where did it originate from?
Definition
 Highway Capacity Software -originated from U of Florida
Term
 CORSIM
Definition
 Corridor Simulation
Term
 5 things in HCS
Definition
 -critical lane group -v/s ratio (demand) -capacity and saturation flow rate -LOS - effective green time (g)
Term
Definition
 -adding lanes -decrease demand (traffic) -optimum phase
Term
 IVHS -> ITS
Definition
 Intelligent Vehicle Highway Systems -> Intelligent Transportation Systems
Term
 Examples of ITS
Definition
 -ABS -GPS -Side/Front Airbags -Cruise Control -TMC (traffic management centers)
Term
 Examples of congestion pricing
Definition
 -short term vs. long term parking -commuters - toll bridges -parking meters -Central Business District
Term
 Bottom line is the driver! % of accidents that are drivers fault?
Definition
 -60-90%
Term
 ideal bandwith =
Definition
 45 sec
Term
 Good bandwidth efficiency =
Definition
 40-55%
Term
 4 types of progressions
Definition
 -simple progression -forward progression -flexible progression -reverse progression -alternate progression
Term
 undersaturated vs. oversaturated
Definition
 undersat - v/c < 1 oversat - v/c >= 1
Term
 When networks are congested, 3 objectives
Definition
 -maximize throughput -utilize storage -equitable service
Term
 reserving
Definition
 going back to a phase more than once in a cycle
Term
 4 classifications of congestion
Definition
 light moderate heavy oversaturated
Term
 3 types of metering
Definition
 internal external release
Term
 remedy for oversaturation
Definition
 shorter cycle lengths
Term
 Offset
Definition
 difference between the time when the upstream intesection turns green and the downstream intersection turns green   ex t2 - t1
Term
 bandwidth
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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