Unit 2 Flashcards
Name the four primary roadway classifications and briefly describe each.
Freeways-limited access, facilitates travel over long distances.
Arterials/major roads- primary, move traffic and allow access to other streets (state routes, cut all the way through a city to the next one).
Collector streets-secondary, collect traffic from local streets, divided into major and minor.
Local/residential streets-tertiary, serve local land uses.
Explain the term “right-of-way” as it relates to roadways.
Rights-of-way are easements that allow the public to travel across private property and are primarily used for roadways, maintained by the government. Roadways, bike lanes, and sidewalks, are all located within the right-of-way.
City may reserve more of right-of-way than current roadway needs in case of future widening. Also allows for good sight distance and access location.
What are the primary advantages of multiple connections in a roadway network?
- Provides multiple travel paths (connects to at least other public streets)
- Ensure alternate access (in emergency)
- Distributes traffic, reduces congestion
Briefly describe the term “levels of service” as it relates to roadway network
capacity. What constitutes an “acceptable” level of service for most communities?
- Measure of effectiveness to assess how a roadway system can accommodate traffic demand. Measured in terms of the amount of time a vehicle has to wait to pass through an intersection
- 6 different levels (A-F)
- (standards vary between unsignalized and signalized).
- • For most communities, especially those that don’t want to be entirely auto focused, a ‘C’ or ‘D’ (85%) is an acceptable level in order to better accommodate other modal options and built environment considerations.
What are approximate typical daily in-and-out trip rates for single family, general
office, and high-turnover restaurant uses? How do these different rates impact
roadway networks
Land use Size Daily Trip Rate
Single family 100 DUs 960
Office 100,000 sq ft 1,100
Restaurant 8,000 sq ft 1,120
List 4 typical roadway facility types and their corresponding ADT volumes.
Type of facility ADT volume
2-lane road without left turn lanes Less than 5,000
2-lane road with left turn lane 5,000 to 20,000
4-lane road with left turn lane 20,000 to 35,000
6-lane road with left turn lane 35,000 to 45,000
What does ADT mean and how does it relate to the design of roadway types?
ADT-average daily traffic. The greater the ADT, the more capacity a roadway needs to have in order to maintain an acceptable LOS.
Briefly describe the difference between road classification as typically done by
engineers and road classification as typically done by design professionals?
Engineers use conventional road classification terminology which emphasizes carrying capacity, efficiency and throughput. Design professionals such as new urbanists (CNU) use terminology that focuses more on multi-modal roadway design such as complete streets. Today, advocates for CNU approach have made such progress that a hybrid of both classifications is used in many major cities.
(see study guide graph)
What are the primary elements of Transit Oriented Development (TOD)?
Transit oriented development, or TOD, is generally defined as mixed-use residential and commercial development that is designed to take advantage of public transportation access. Multimodal, ped-friendly design, mix of compatible uses, connectivity to surrounding community and mix of housing options.
What is a Thoroughfare Plan? Briefly explain its significance and value for a
community.
- Long-range plan that identifies the location and type of roadway facilities needed to meet community’s projected long-term growth
- Enables government to plan ahead for future roadway expansion, guide development, and anticipate needs
- Impact on land use and community character must be considered
What are Traffic Analysis Zones and what is their purpose in regional traffic
planning?
- Unit of measurement used in transportation planning models used by MPOs, used for compiling and tabulating traffic related land use and socioeconomic data
- Gives 30 year estimates of future land-uses and densities and their impact on traffic patterns
- Recommends types of facilities that will be needed
- Data collected via surveys, GPS data, Census
- Zone size based on population (ie. smaller zones in dense urban areas) and Census data (vehicles per household, income, etc.)
Name 2 policy decisions available to a community in order to mitigate traffic congestion. Briefly explain the impacts of each.
- Expand roads-enhance capacity. The problem with this policy is that eventually it will lead to intersections with an exorbitant number of lanes which require special design (eg. double left turn lanes, drop off right turn lane, special signal time).
- Control land use- In contrast, this policy controls development, which limits population growth and the need for more capacity. It allows for narrower streets, less congestion, more multimodal/ped.-friendly.
- The desirability of one option over the other varies on a case-by-case basis.
List three (3) Access Management methods and describe the advantages of each and the challenges in accomplishing each.
Access Spacing: increase distance between traffic signals
Advantages: Improves traffic flow, air quality, reduces congestion
Challenges:
Requires long-term planning
Reduces path options
List three (3) Access Management methods and describe the advantages of each and the challenges in accomplishing each.
Median Treatments: Nontraversible, raised medians
Advantages: Limit turning movements and conflict points
Slows traffic
Aesthetically pleasing
Ped.-friendly
Challenges: Must have adequate space for installation
List three (3) Access Management methods and describe the advantages of each and the challenges in accomplishing each.
Cross Access: Connect adjacent parking lots
Advantages: Relieves congestion on roadway network
Allows for looser standards in parking lot design
Efficient use of space since each business doesn’t have to meet capacity standards
Challenges: Must get property owners to coordinate and cooperate
Properties with different grades must be altered (under 15% grade)
