Adopted by the Iowa Transportation Commission
May 11, 1999
Iowas roadways serve several modes of transportation
including trucks, automobiles, buses, motorcycles, bicycles, and pedestrians.
Bicyclists carry the same rights and responsibilities, as motor vehicle
drivers are currently legal on virtually all public roadways in Iowa.
It is federal transportation policy to "promote increased
use of bicycling, and encourage planners and engineers to accommodate
bicycle and pedestrian needs in designing transportation facilities for
urban and suburban areas." The Iowa Department of Transportation will
consider the needs of all transportation users and also encourage metropolitan
and regional planning agencies to plan for bicycle and pedestrian accommodations
in their areas.
Bicycle accommodation guidance
The departments policy is to provide safe, convenient
and adequate bicycle facilities along the state highway system. As part
of the development of every highway construction project, the department
will consider the following situations to determine whether further bicycle
accommodation is needed within the highway corridor.
- When highways in and around rural communities are the primary means
of bicycle transportation due to the limited availability of other facilities.
- When the highway provides primary access to a park, recreational area
or other significant destination.
- When the highway provides unique access across a natural or man-made
barrier, i.e., bridges over the rivers or roads or over/under access-controlled
facilities and roadways.
- The highway provides a connection in an otherwise continuous bicycle
- When the highway project negatively affects the recreational or transportation
utility of an independent bikeway or trail. Highway projects will negatively
affect at-grade paths and trails when they are severed, when the projected
roadway traffic volumes increase to a level that prohibits safe crossings
at-grade, or when the widening of the roadway prohibits sufficient time
for safe crossings.
The department will also provide further bicycle accommodation
within the highway corridor if a Regional Planning Affiliation (RPA) or
Metropolitan Planning Organization (MPO) can provide a forecast of the
bicycle traffic five years after project completion that shows the volume
of two-way bicycle traffic averages at least 25 bicycles per day during
the peak three months of the bicycling season and motor vehicle traffic
on the highway or street exceeds 1,000 vehicles per day. The forecast
of bicycle and motor vehicle traffic will be reviewed and approved by
the department. In addition to the forecast, the RPA or MPO will show
through an analysis of alternatives, that the best alternative is accommodation
within the state highway corridor. The department will provide a methodology
to the RPAs and MPOs to follow when developing the travel forecasts and
when evaluating alternatives.
The department will utilize the AASHTO Guide for the
Development of Bicycle Facilities as the basis for design guidance.
Further guidance is provided in FHWAs Selecting Roadway Design
Treatments to Accommodate Bicycles.
The location of the bicycle accommodation may be on the
highway (e.g. bike lanes, paved shoulders, etc.) or off the highway as
a separated bicycle path. In most cases, the preferred location of bicycle
accommodation is on the highway. The AASHTO Guide for the Development
of Bicycle Facilities lists several reasons bicycle accommodations
are preferred on the highway:
- At intersections, motorists entering or crossing the highway often
will not notice bicyclists on separated bicycle paths approaching from
their right, as they are not expecting contra-flow vehicles. Motorists
turning to exit the highway may likewise fail to notice the bicyclist.
Even bicycles coming from the left often go unnoticed, especially when
sight distances are limited.
- Signs posted for roadway users are backwards from contra-flow bike
traffic on separated bicycle paths, and therefore these cyclists are
unable to read to read the information without stopping and turning
- Many bicyclists will use the highway instead of the separated bicycle
path because they have found the highway to be more convenient, better
maintained, or feel safer riding on the road.
- Although the separated bicycle path should be given the same priority
through intersections as the parallel highway, motorists falsely expect
bicyclists to stop or yield at all cross-streets and driveways. Efforts
to require or encourage bicyclists to yield or stop at each cross street
and driveway are inappropriate and frequently ignored by bicyclists.
- Stopped cross-street motor vehicle traffic or vehicles exiting side
streets or driveways may block the separated bicycle path crossing.
In some cases, a separated bicycle path may be appropriate
due to the factors such as traffic volume, type of motor vehicles, traffic
speed, and skill level of users.
Types of bicycle improvements/design treatments
There are several ways in which roadways can be constructed
to enhance bicycle transportation. Adding or improving shoulders can often
be a feasible way to accommodate bicycles in rural areas. Bicycle lanes
and wide curb lanes are the primary improvements for urban areas, where
available road space is a concern. The following design treatments are
extensively explained in the AASHTO Guide for the Development of Bicycle
- Shoulders: A paved portion of the roadway to the
right of the edge stripe. AASHTO recommends paved shoulders specifically
for bicycle accommodation improvements in rural areas. Shoulders will
be paved in accordance with design standards and paved shoulder studies.
Bicycle traffic on a paved shoulder will typically be one-directional
with the flow of traffic; therefore both shoulders will be paved when
providing accommodation for bicyclists.
- Wide curb lanes: An outside travel lane on highway
sections with a width of greater than 12 feet (14 feet typically).
Used primarily in urban areas, the wide curb lanes can allow road use
by both bicyclists and motorists without conflict.
- Bicycle lane: A portion of the roadway, which has
been designated by striping, signing and pavement markings for the preferential
or exclusive use of bicyclists. Bicycle lanes should always be one-way
facilities carrying traffic in the same direction as adjacent motor
vehicle traffic, and they should not be placed between parking spaces
and the curb. Bicycle lanes offer a channelizing effect on motor vehicles
- Separated bicycle path: A bikeway physically separated
from motorized vehicular traffic by an open space or barrier, and either
within the highway right-of-way or within an independent right-of-way.
Incidental design factors that improve the safety of
bicycle travel will be considered on all state highway improvements. These
include, but are not limited to:
- Drainage grates and utility covers suitable for bicycle travel
- At-grade railroad crossings that accommodate bicycle movements
Consideration of bicycle accommodation will occur at
all stages of planning and project development. When feasible, the recommended
design treatments will be implemented as part of new construction, reconstruction,
or preservation of the roadway.
Accommodations requiring grading and/or the purchase
of right-of-way will normally not be considered as part of a highway preservation
improvement. Consideration of bicycle accommodation will not occur as
part of highway maintenance activities. When accommodation is provided
as part of a highway improvement project, the cost for the facility will
be considered an additional highway construction cost.
Providing bicycle accommodation independent of a highway
construction project will be considered with construction funding obtained
from local jurisdictions or other federal and non-road use tax state sources.
Pedestrian accommodation guidance
- The department will be responsible for the ongoing maintenance of
bicycle facilities within the state highway right-of-way.
- The department will not be responsible for maintenance of bicycle
facilities outside the state highway right-of-way.
The department will consider the impacts to pedestrian
accommodation at all stages of the project development process and encourage
pedestrian accommodation efforts when impacted by highway improvements.
Cost of these accommodations made at the time of the highway improvement
will be considered additional roadway construction costs. Providing pedestrian
accommodation independent of a highway construction project will be considered
with construction funding obtained from local jurisdictions or other federal
and non-road use tax state sources.