Speed limits are often based on observed 85th percentile free flow speeds. Setting them lower, even to address safety concerns, can be difficult once engineering recommendations have been made. A new study, however, bolsters the case for doing so by showing that setting limits just below the observed speeds can reduce crashes, including the most serious ones.
design standards
Lowering speed limits can reduce crashes
Speed limits are often based on observed 85th percentile free flow speeds. Setting them lower, even to address safety concerns, can be difficult once engineering recommendations have been made. A new study, however, bolsters the case for doing so by showing that setting limits just below the observed speeds can reduce crashes, including the most serious ones.
Toward livable streets: A review of recent improvements in practice
In the last decade a number of project development and design guides, such as ITE’s “Designing Walkable Urban Thoroughfares,” NACTO’s “Urban Street Design Guide,” and city design guide manuals, have emerged. A new article by Eric Dumbaugh of Florida Atlantic University and Michael King of BuroHappold Engineering, reviews these updated practices. The article finds four general principles of livable streets engineering.
Portland guide to streamline protected bicycle lane design
In the United States, bicycling mode share hovers in the single-digits, while many European countries enjoy double-digit cycling mode share. The difference may be due to the attention European planners and engineers pay to cycling infrastructure. In Portland, OR, a recently-previewed bicycle lane design guide will become the go-to resource for Portland’s planners and traffic engineers when designing protected bike lanes.
Florida DOT hits milestone in context-based street design
As part of its Complete Streets Implementation, the Florida Department of Transportation recently adopted eight context classifications to guide road design decisions. Under this new system, planners and engineers will consider existing and future characteristics such as land uses, building configuration, and street connectivity to ensure that roads are designed for the right vehicle speeds, road users, and trip types.
FDOT makes strides in Complete Streets implementation: Former Dist. 1 Secretary Billy Hattaway weighs in
The Florida Department of Transportation has achieved a major milestone in its efforts to improve pedestrian and bicycle safety. In late April, FDOT issued a draft of the new FDOT Design Manual, which integrates a context-sensitive Complete Streets approach and will replace the agency’s current Plans Preparation Manual. FDOT has also released a draft of its new Complete Streets Handbook to accompany the Design Manual. SSTI spoke with Billy Hattaway, P.E., former Secretary of FDOT District 1, about the Complete Streets implementation efforts.
September webinar: A guide for complete transportation—Arizona DOT’s new design guide
In case you missed our September webinar: In February, Arizona DOT published its much-anticipated Complete Transportation Guidebook, which ADOT views as a conversation about integrating sustainable transportation practices into the planning, scoping, and design of the project development process. The guide seeks to incorporate multiple transportation modes and is meant to be accessible to government agencies at all levels that work on transportation projects. By providing guidance on available infrastructure choices with a complete transportation approach that covers the planning, scoping, and design of transportation improvement projects, ADOT is hoping to instill sustainability practices both inside and outside the agency. A recording is available on our website.
Can Florida design its way to safety? SSTI meeting highlight
In a presentation to the SSTI’s Community of Practice meeting earlier this month, Billy Hattaway, Florida DOT’s District One Secretary, described his agency’s ongoing efforts to improve statewide safety through road design and attention to land use. He emphasized that he prefers to see safety improvements made through engineering solutions, before relying on education and enforcement. The state’s complete streets initiative is a focal point of its recent efforts.
FHWA proposing new road design policies for greater flexibility
Earlier this month the FHWA announced a proposed change to its design standards that are currently applied to all highway projects. The changes are intended to give engineers and planners much more flexibility and autonomy by eliminating outdated standards. For roads with a speed limit below 50 mph, the proposal seeks to remove 11 of the 13 design criteria; for roads over 50 mph, three criteria would be removed. In August, FHWA released a document that addresses some misconceptions about how federal funding can be used and when a design exception must be requested. It emphasizes that federal rules and funding are significantly more flexible than has been portrayed in the past.
MassDOT implements policies to increase walk, bike, and transit travel
In support of its goal to triple walking, biking and transit travel by 2030, the Massachusetts DOT has issued a Healthy Transportation Policy Initiative with several implementation steps.