PORTS - TRIP GENERATION AND DISTRIBUTION
Predicts the total number of trips by trip purpose, generated by or attracted to each zone of a study area. It is a function of land use, accessibility, and socioeconomic factors, such as income, race, and vehicle ownership. This lesson illustrates how to incorporate these inputs to estimate trips generated from and attracted to each zone using regression methods, crossclassification models (tables), and rates based on activity units (ite). It also provides examples to demonstrate the model applications
Trip Generation
- Land Use Characteristics
- Socioeconomic Factors
- Demographic Factors
-Transportation Infrastructures
Factors affecting trip generation
The type and intensity of land use have a significant impact on trip generation. Different land uses, such as residential, commercial, industrial, or recreational, have varying trip generation rates based on their activities, size, and purpose.
Land use characteristics
Socioeconomic factors, such as population density, household income, employment opportunities, and educational institutions, influence trip generation. Areas with higher population densities or employment concentrations tend to have higher trip rates.
Socioeconomic factors
Demographic characteristics, such as age, gender, and household size, also play a role in trip generation. Different age groups and household compositions have distinct travel patterns and trip generation rates.
Demographic factors
The availability and quality of transportation infrastructure impact trip generation. Factors such as the presence of highways, public transit systems, sidewalks, and bike
lanes influence the mode of transportation chosen and subsequently affect trip generation.
Transportation infrastructure:
We must divide the study area into traffic analysis zones (tazs) connected via transportation networks and facilities to perform an accurate traffic analysis associated with human activities in a
region or city.
Trip Generation Calibration
Are the tiniest units of fsm analysis, and transportation networks or natural boundaries (e.g., rivers) must separate them
Tazs
A one-way person movement by a mechanized mode of transport. a trio generally has two trip ends.
Trip
Each trip starts at one location or zone and ends at another location or zone. the starting point or zone is called the ______,”and the ending ____________
point or zone
Origin & Destination
Refers to the origin of trips in the study area. Since most trips originate at the home end, it can also be the home end of home-based trips.
Trip production
the non-home end of home-based trips (alkaissi, 2021)
Trip attraction
The trip generation model uses annual or daily trip generation rates calculated based on human activities, population, and employment stats. We can estimate trip generation rates by calculating the average weekday peak-hour trips generated by a particular land use. _______ for each land-use type is the total number of weekday peak-hour trips. The institute of transportation engineers publishes this rate based on field observations (ite, 2017).
Trip generation rates
Trips for which the destination is not a final but a stop along the way by using the connecting roads. Passing-by traffic volume in a zone depends on development types, size, or available activities. a gas station near a rich employment center may receive many pass-by trips for gas compared to other gas stations (where up to 50 % of all trips to a service station are travelers passing by rather than people who made a special trip to the gas station)(meyer, 2016).
Pass-by trips
Trips produced from the traffic flow in the adjacent area of the trip generator that needs diversion. this new traffic will be accumulated in the roadways close to the site
Link-diverted trips
Home-Based Work (HBW)
1. Origin-destination
2. Destination-origin
1. Home
2. Work
Home-Based Non-Work (HBNW) or Home-Based Other (HBO)
1. Origin-destination
2. Destination-origin
1. Home
2. Other
Non-Home-Based (NHB)
1. Origin-destination
2. Destination-origin
1. Other/Work
2. Work/Other
This segment describes the second step of the four-step travel demand modeling or trip distribution. It focuses on the procedure that distributes the trips generated from or attracted to each zone in the study area. in this step, the trip distribution input is the trip generation step’s output and the interzonal transportation costs. based on the concepts of the gravity model, the trip flows between each pair of zones can be calculated as an od matrix. the segment discusses essential concepts and techniques, such as growth factors and calibration methods
Trip Distribution
It depends on several factors (Cesario, 1973)
- Uniqueness
- Distance
- Closeness to other services
-Urban or rural area
The level of attractiveness of a zone
This factor indicates how unique a service or employment center is and thus attracts more trips regardless of distance
Uniqueness
the distance between two zones plays an impedance role, meaning that the further the two zones are from each other, the fewer trips will be distributed between them
Distance
We assume that wherever is more approximate to other attractive services will attract more trips within an urban area
Closeness to other services
We assume that whether the zone is urban or rural, the attraction rate for the zone would be different when controlling for other factors.
Urban or rural area
the total trip attraction/ destinations must be equal to total trip productions. as trip production is considered to be exact
Adjustment Factor
The difficulty of moving from one node to another in a network is the link impedance. impedance in electrical terms means total resistance and for transport the meaning is the same
Impedance
For modeling _________ can be expressed as distance but travel time or apparent costs are usually better measures. arbitrary units that are functions of impedance factors may be more
convenient than actual measurable quantities for modeling purposes
Link Impedance