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40 Cards in this Set

  • Front
  • Back
5 general principles of the MUTCD
fulfill a need, command attention, convey clear, simple message, command respect of road users, give adequate time for proper response
3 critical aspects of traffic control devices addressed by the MUTCD
standards for physical design of the device, specifying shape, size, colors, legend types and sizes, 2-where devices should be located, 3-warrants that justify use of a particular device
4 different categories of the legal aspects of the MUTCD
standard, guidance, option, support
4 mechanisms to convey messages to drivers by traffic control devices
color, shape, pattern (such as double yellow or dashed), legend (words on signs)
shall, should, and may used in the MUTCD – their implications
standards use shall, guidances use should or should not, options use may or may not
MUTCD
Manual on Uniform Traffic Control Devices
semi-actuated control
used where small side street intersects major street, two phase with all turns permitted
full actuated control
all lanes of all approaches monitored by detectors, cycle lengths subject to variation, accommodates multi-phase
volume-density control
same as full actuated with additional demand response features
gap reduction
smaller gaps required as time progresses in order to maintain green for the phase
6 Features and operations of actuated signals
min. green time, passage time (PT), max green time, recall settings, yellow & all-red intervals, pedestrian WALK
6 components of the HCM 2010 signalized intersection models
input module, define movement groups and adjusted flow rates, compute lane group flow and saturation flow rates, input or compute phase duration, compute capacity, compute performance measures
difference between critical lane and critical lane group concepts (24.2.1)
HCM uses critical lane instead of lane group since it accounts for unequal use of lanes through a process of adjustments to saturation flow rates
Effect of changing offsets (26.3
changes bandwidths
Potential problems of coordination (Course notes)
increasing bandwidth efficiency in one direction could decrease efficiency in another
bandwidth
time difference between the first and last vehicle that can pass through the entire system without stopping
common types of progression (26.6)
simple, forward, flexible, reverse
bandwidth efficiency
bandwidth / cycle
how max green is timed
begins when there is a "call" on a competing phase
how min green may be estimated for point or presence detection (2 equations)
Gmin = start-up lost time + 2 * int(dist between STOP line and detector / 25)

Gmax = start-up lost time + 2 * number of veh stored in detection area
point detection passage time is the same as...
PT = MAH (max allowable headway)
presence detection passage time (equation)
PT = MAH - (length veh + length detection zone) / (1.47 * avg approach speed)
capacity of a lane group
c = sat flow rate* (eff green / Capacity)
degree of saturation ( v/c ratio)
actual flow / capacity
flow ratio (v/s)
actual flow / saturation flow rate
degree of saturation for an intersection
(v/s) / (g/C) or (actual flow / saturation flow rate) / (eff green / cycle length)
X = v/c = ?
= (v/s) / (g/C)
arrival type (equation)
AT = 3* P / (g/C) or 3*proportion of vehicles arriving on green / (eff green / Cycle length)
arrival types 1-6
progression quality increases from 1 to 6, density increases moving up or down from #3
relation between flow rate, volume, PHF
v = V / PHF or flow rate = volume / peak hour factor
desribe the 4 cases in figure 24.8 (pg 593)
initial queue? residual queue?
explain d = d1 + d2 + d3
avg control delay per veh = avg uniform delay per veh + avg incremental delay per veh + additional delay per veh due to queue
sneakers equation
additional eff green used by sneakers = 2*(1+ proportion of veh in left lane) / eff green
ideal offset
t(ideal) = length of block / vehicle speed
simple progression
all signals set for vehicle released from 1st intersection arrives as green phase begins
forward progression
vehicles advancing from simple progression
flexible progression
progression coordination changes during the day to meet peak demand direction
reverse progression
results when ideal offset is large
alternate progression
works for 50:50 splits, uses (C / 2) = (L / S), where L = block length and S = platoon speed... 50% efficiency
double-alternate progression
25% efficiency so C = 4L / S