GLOSSARY

AASHTO.  American Association of Highway and Transportation Officials.  AASHTO provides guidelines for the design of vehicular, bicycle and pedestrian facilities.

Bike lane.  A portion of a roadway designated for bicycle use and delineated by pavement striping and markings and sometimes accompanied by signage.  AASHTO recommends a 5-foot bike lane width from the face of the curb (including the gutter; a standard 1.5 feet in Ann Arbor) and a minimum rideable surface of 3 feet. 

Bike route.  A designation that can apply to any type of bicycle facility.

City of Ann Arbor Non-motorized Transportation Plan.  Adopted by City Council as an element of the Master Plan in January 2007, this document provides planning and design guidelines; proposed policies and programs; existing conditions and proposed facilities for non-motorized transportation.  The document can be viewed on the City’s web site.

Clear zone or clear traveled way.  The area clear of obstructions on shared use paths or sidewalks.

Clearance, horizontal or lateral.  Distance from the edge of a roadway, pedestrian or bicycle facility to a vertical obstruction.  For rail facilities, the distance from the center line of the track to the bridge supports.

Clearance, vertical.  Dimension from the roadway, railroad track, pedestrian or bicycle facility surface to an overhead obstruction, measured from the surface (or top of rail) to the lowest point of the overhead obstruction.

Federal Sufficiency Rating (FSR).  Federal Sufficiency ratings are calculated based on bi-annual MDOT bridge safety inspections and determine eligibility for MDOT’s Local Bridge Program funding.  Bridges with an FSR of 80 to 100 are eligible for preventive maintenance, between 50 and 80 are eligible for rehabilitation and less than 50 for replacement funding.

MDOT.  The Michigan Department of Transportation.

MDOT railroad clearance standards.  These standards include the following:

*  Note: lateral clearances are greater for Conrail (16’-0”) and CSX (15’-0”)

Minimum dimensions/clearances.  Minimum dimensions/clearances are requirements established by a regulatory agency such as MDOT.  They represent the minimums for use in design of new facilities.

Preferred dimensions/clearances.  Preferred dimensions/clearances are recommended values published by a regulatory agency such as MDOT which can be used at the discretion of the engineer when designing new facilities.  Their use is considered in the context of other factors (for example, cost, risk, loss of mature trees).

Public Act 51.  Michigan’s Public Act 51 governs the use of tax revenues collected on motor fuels and vehicle registration and deposited in the Michigan Transportation Fund.  A portion of these funds are allocated to Michigan cities as a match for locally raised funds used for maintenance, construction and improvement of major and local streets.

Raw water main.  Water main used to carry untreated water directly from a source (such as a river) to a water treatment plant.

ROW.  Right-of-way.

Sidewalk.  A paved pathway paralleling a street intended for pedestrians.  On arterial streets, AASHTO recommends a clear width of 6 feet to 8 feet when a landscape buffer is provided between the sidewalk and the street.  Where the sidewalk is flush against the curb, a width of 8 feet to 10 feet is recommended.

Shared use path.  A path shared by pedestrians and cyclists with travel allowed in both directions.  AASHTO recommends a minimum shared use path width of 10 feet (clear traveled way) with a minimum of two feet clearance to lateral obstructions (such as walls, signs, or light standards) on either side.

Shared roadway.  A roadway with a widened outside travel lane of 14 – 15 feet to allow for cycling, but not specifically designated for bicycles.  This dimension provides for an 11-foot travel lane for motorists and a 3- to 4-foot bike zone.

Sidewalk bikeway/sidepath.  A type of shared use path that parallels a roadway.  AASHTO recommends designating a sidewalk as a signed bikeway only in limited circumstances, including (1) to provide bikeway continuity along high speed or heavily traveled corridors with inadequate space for cyclists and (2) uninterrupted by driveways and intersections for long distances.