TP exam2 Flashcards
4 steps of the traditional four–step process of urban travel demand
Trip Generation, Trip Distribution, Mode Split, Traffic Assignment
Trip Generation (inputs, outputs, and models)
socioeconomic conditions and land use (in), productions/attractions (out) w/linear regression model
Trip Distribution (inputs, outputs, and models)
productions/attractions (in), trips (out) w/gravity model
Mode Split (inputs, outputs, and models)
trips (in), trips by mode (out) w/Logit Model
Traffic Assignment (inputs, outputs, and models)
trips by mode (in), travel time and level of service (out) w/user equilibrium or system optimal
There are two different types of modal split models identified in the text – what are they?
Trip–End Models & Trip–Interchange Models
Define the logit model including a mathematical representation of the model and definitions of each term.
traveler with a choice tends to choose the travel mode that has the greatest utility\nP = e / sigma e equation…
Trip–End Models, definition, (when should it be used, and why?)
based on assumption that ridership is due to socioeconomic variables “captive” users; use before trips distributed; used for small\ncommunities or in developing countries
Trip–Interchange Models, definition, (when should it be used, and why?)
Logit model, use after trip distribution, looks at multiple socioeconomic factors and trips to determine split
Trip assignment – Interaction between supply and demand ?
demand – output from first three steps of process, supply – network (roadway, transit routes) and costs (travel time, distance, tolls)
user equilibrium
based on the assumption that each individual chooses the route perceived as being the best
system optimal
users are assigned to routes so as to minimize the system wide average cost of travel, generally does not yield same result as user equilibrium
4 traffic assignment techniques outlined in Section 5.4.4 of Meyer & Miller’s text
minimum path (all–or–nothing), equilibrium assignment, stochastic assignment, dynamic assignment
minimum path (all–or–nothing)
all traffic between a given origin and\ndestination is loaded on the links comprising the minimum path and nothing is loaded on the other links
equilibrium assignment
volume on links change until travel time on links become the same
stochastic assignment
user equilibrium, based on the assumption that each individual chooses the route perceived as being the best (i.e., each individual\nminimizes or optimizes travel time or cost)
dynamic assignment
similar to user equilibrium, but this method assigns trips over time as well
incremental assignment methods
assignment by link or node – assign increment of flow and then update travel times, then assign another increment of flow on new shortest time
Basics of urban planning theory.
planner’s objective is not merely to describe the city and its components, but rather to propose ways in which they can be changed,
3 basic concepts used to describe urban form
urban form, urban interaction, and urban spatial structure).
urban form
the spatial pattern or “arrangement” of\nindividual elements
urban interaction
collective set of interrelationships, linkages, and flows (i.e., highways and streets)
urban spatial structure
Combines the urban form through the urban interaction with a set of\norganizational rules into a city system (i.e., rent, density, income)
Comprehensive plan, master plan, or general plan:
An official statement of a geographic unit’s policies and intentions pertaining to physical development in\nthe years ahead.
