Design Guidelines (Mulitmodal Streets)
Streets are not considered in isolation from land use, but are defined in part by the buildings and land uses that are located next to them. Streets are comprised of the area where vehicles move, the area where pedestrians move, and the areas where buildings interface with the rest of the street. Designing multi-modal streets ensures that the design of the entire right of way – travel lanes, parking, bike lanes, medians, sidewalks, and street trees – are appropriate to and complement the adjacent land use. Multi-modal street types and land use types become the primary components of integrated land-use and transportation decisions.
All streets are multi-modal streets in that they accommodate multiple travel choices, trip purposes and travel lengths. The primary challenge with multi-modal street design is that no two multi-modal streets are generally designed the same due to the difference between mobility, access, interface and travel modes associated with each street. The street function designation defines the broad purpose of the street, such as the need to primarily move vehicles or primarily provide land access.
Corridor Simulation (Mulitmodal Streets)
Manzanita is a two lane road through an environmentally-sensitive area adjacent to Bidwell Park in Chico, California. Traffic analysis and forecasts indicated that the road would need to be widened to four lanes to provide sufficient congestion relief. In addition to the corridor's environmental sensitivity and recreational uses, physical constraints such as homes and utilities were present. Fehr & Peers analyzed a variety of two, three, and four-lane alternatives, including variations on lane widths, turn lanes, and intersection control. All of the traffic operations analyses were conducted using the CORSIM and VISSIM micro-simulation traffic models. The VISSIM model was used specifically to evaluate an alternative containing roundabouts at key intersections. The study concluded that a two-lane roadway with roundabout traffic control at key intersections would provide sufficient capacity; thereby striking a balance between mobility and the environment. Based on this study, the City of Chico is revising their General Plan to maintain Manzanita Avenue as a two-lane roadway.
PedINDEX GIS Analysis
A robust GIS tool for creating walkable pedestrian environments
Pedestrian planning is centered on the creation of walkable pedestrian environments, including livable streets, connected pedestrian networks, and context-sensitive land uses. Pedestrian Master Plans can outline a process for creating these environments through policy recommendations and capital improvements directed toward “pedestrianizing” streets and neighborhoods. Geographic Information Systems (GIS) applications are a powerful tool for assessing a community's pedestrian needs and prioritizing improvements.
A useful, robust process for identifying the top priority improvements involves the use of the PedINDEX, which has been adapted from the Environmental Protection Agency's Smart Growth INDEX. The PedINDEX combines composite indices for walking demand and pedestrian deficiencies to yield an overall index of the areas with the highest walking potential (i.e., supportive land use, demographic and socio-economic factors) and worst pedestrian facilities (i.e., areas lacking sidewalks, street lighting, etc.). The premise is that these are the areas where the greatest safety benefits and increases in the number of people walking can be achieved through the implementation of pedestrian improvements.
Bicycle and Pedestrian Networks
Tools for planning and implementing connected bicycle and
pedestrian networks
Connected, continuous bicycle and pedestrian networks are key to a well-functioning multimodal transportation system. Such networks – a component of the “design” element of the 4-Ds – enable more people to walk and bike, and help reduce automobile-dependence. As part of the development of its Smart Growth INDEX model, the Environmental Protection Agency (EPA) identified factors which could influence the decision to bicycle or walk. These factors were assigned a weight which, when taken together, measure an area's “bikeability.” A bikeability analysis tool helps identify locations that have the greatest potential to serve a large number of cyclists.
The factors identified that have a measurable impact on the decision to bicycle include:
- Presence of/proximity to a university or college
- Population density
- Employment density
- Land use mix
- Proportion of zero-vehicle households
- Proximity to transit
Many of the above factors can be readily analyzed through GIS modeling tools. Similarly, walkability can be assessed through a GIS analysis of “pedestrian demand.”
