Travel speed
overall average speed
fixed delay
delay regardless of the amount of traffic
operational delay
interference from other components of the traffic stream
Parking Turnover
Turnover = #parkedvehicles / #spaces
LRTP
Long range transportation plan
* consideration of a full range of modal choices and connections between modes to meet short and long term needs
* predicts future land uses
TIP
Transportation improvement plan
* priority projects to be implemented over next three years
LTRP Steps in modeling
- Long Range Transportation Planning
- Trip generation
- Trip distribution
- Mode split
- Trip assignment
Control delay
delay attributed by traffic control device, plus time decelerating to a queue, waiting in queue, and accelerating from queue
Regression to the mean
when period of high crash frequency is observed, the following period will have comparatively low crash frequency
delay definition
additional travel time experienced by driver, passenger, or pedestrian
intersection delay study
* recommended amount of sample intervals
* increments between samples
- at least 60 intervals
- 13 - 20 second intervals
recommended sample size for studies
100 vehicles per lane
true speed equation
(radar gun)
measured speed / cos (a)
AADT
- average annual daily traffic
- 24-hour volume at a given location over a full year
ADT
- average 24-hour volume for period less than a year
- can be calculated for a month, a week, or two days
DHV
- design hourly volume
- one hour volume (or flow rate)
16-hour counts (typical hours)
(accounts for what % of daily traffic)
- 6am - 10pm
- 90% - 95% of daily traffic
12 hour counts (typical hours)
(accounts for what % of daily traffic)
- 7 am - 7pm
- 75% of daily traffic
Volume Adjustment Factors
f = AADT / Month AADT
Parking duration equation
Duration = (#observations * time interval) / # vehicles
