Lec 25: Ch2.(T&LD): Site planning

Understand the difference between the “linear” site planning process and systems approach

Know what may be involved in reviewing a proposed land development

Understand the the scale of development requires different levels of traffic analysis and facility design

Understand we need to have a conceptual plan (or a preliminary plan) in order to identify alternatives and associated problems before we get involved in detailed planning and design

Pitfalls of “linear” site-design process

Building location & design

On-site parking & circulation

Access location & designNo feedback

Possible problems of the linear process:• Inadequate access capacity• On-site congestions• Congestion on the public street system• High accident experience• Limited flexibility to adjust the design or operation to changed conditions

Access design is like an “after thought”

Benefits of the systems approachLots of feedback opportunities

Involve the traffic engineer from the beginning!

Before building location and design are finalized and financial commitments are made, estimate potential traffic impacts on the site and the off-site, affected areas and identify possible solutions.

Proposed Development Review (PDR) ProcessConsisting of:

Financial feasibility study Determine the market area of influence, the projected build-out/lease-out period, and the potential short- and long-term return on investment.

Site-plan review: Site design, access location and design, and other elements

See page 19 for check items Traffic impact analysis (TIA) a

specialized study of the impact a certain type and size of development will have on the surrounding transportation system. The first two items define the scale of TIA required

T I ATIA Concerned with the generation, distribution, and assignment of traffic to and from a proposed development through the road network surrounding the development. Also TIA is to determine what impact the existing and projected traffic on the roadway system will have on the proposed development.

When is it required? All development which can be expected to generate more

traffic than some specified threshold All applications for rezoning Any change in the use of an existing commercial or

industrial site The previous TIA is more than 2 years old or where

increased land use intensity will result in an increase in traffic generation by more than 15% or a directional distribution in the site traffic by more than 20%

Typical content of a TIA

1. Existing conditions2. Trip generation and design hour volumes3. Trip distribution and traffic assignment4. Existing and projected traffic volumes5. Capacity analysis6. Traffic accidents7. Traffic improvements8. Conclusions9. Summary of findings and recommendations

Sound familiar…

Topics of CEEn 562

Planning scales: Corridor, project, or site planning issues

(Compare the size of impacted area)

Corridor Level Arterials and collectors placement & Impact of the development on these facilities

Planning scales: Corridor, project, or site planning issues (cont)

Project level Impacts on adjacent properties and roadways and the placement of access

Site level parking, building footprint, site circulation

(See Tab 2-1)

Conceptual site plan: An exampleObjective: Identify suitable areas for various developments

Existing transp. network

Major land use planning determinants

Conceptual site plan: An example (cont)

Site characteristics of 6 sub areas, used to determine a preliminary distribution of land use