IDOT Highway Planning and Programming Guidance
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~ Fax: 515-239-1120
May 28,1999
Ref. No. 763
MEMORANDUM TO CITIZENS OF IOWA
FROM: Dennis 1. Tice, Director'::s)(J\
Planning and Programming Division
SUBJECT: Highway Planning and Programming Guidance
.
The Iowa Transportation Commission adopted highway planning and programming
guidance on May I I. This guidance will be the basis for decision making relative to
Iowa primary highway system improvements and investments and is intended to
implement investment directions of Iowa in Motion. This guidance only applies to the
primary road system and will be used in the development of highway projects coming
into the 2000-2004 Iowa Transportation Improvement Program. The guidance
provides policy direction relative to super-2 highways, narrow roadways, bicycle and
pedestrian accommodations, transit accommodations, Commercial and Industrial
Network raiI/highway grade separations, and bypasses.
The guidance approved by the Transportation Commission is very similar to the draft
guidance sent out for public review in January. Based on the public comments we
received, sections of the guidance were clarified and minor modifications were made.
A copy of the approved highway planning and programming guidance is attached. If
you have any questions regarding the guidance, you may call 515-239-1669.
DLT:DGW:SPA:reI
Attachment
Narrow Roadway Guidance
During the Iowa in Motion process the department received many comments
concerning Iowa's transportation system. One of the concerns of many Iowans was
that of narrow roadways on the state highway system. In response to these concerns
the department has developed the following guidance to improve these routes. These
improvements will promote safety and rural mobility.
For purposes of this guidance, narrow roadways are defined as those roads with
pavements 20 feet or less or roadways with a combination of pavement width and
shoulder width less than 30 feet. Roadways meeting these requirements will be
evaluated and prioritized for improvements.
Evaluation Criteria
The Maintenance Division will use the following criteria and weights to determine the
priority of narrow roadway improvements.
. Safety (30 percent)
. Accident rate compared to state average
. School bus trips or transit vehicle traffic
. Roadway Geometries (50 percent)
. Shoulder width
. Pavement width
. Curvature
. Traffic Volumes (20 percent)
. Average daily traffic (ADT)
. Average daily truck traffic
Bridges
Bridges located on sections of primary narrow roadways will be evaluated on a case by
case basis to determine the need for improvement. Some of the factors to be
considered in the determination of structure improvements include structure width,
structure condition, and accident history.
Funding
Funding for this program will be up to 4% of annual DOT Highway Improvement
Program construction expenditures. Any narrow roadway improvement, including
reconstruction, will be eligible under this program. If the improvement is on a route
eligible for transfer of jurisdiction, efforts will be made to reach an agreement with the
local jurisdiction to transfer the route.
Bicycle and Pedestrian Accommodation Guidance
Iowa's 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 and 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 department's 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,
Le., bridges over rivers or railroads or over/under access-controlled facilities and
roadways.
. The highway provides a connection in an otherwise continuous bicycle faCility.
. 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.
Design Guidance
The department will utilize the AASHTO Guide for the Development of Bicycle Facilities
as the basis for design guidance. Further guidance is provided in FHWA's 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 the
information without stopping and turning around.
. 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 factors such as
traffic volume, type of motor vehicles, traffic speed, and skill level of users.
Types of Bicycle ImprovementslDesign 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 Facilities.
. 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 and bicycles.
. 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
Implementation
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 andlor 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.
Maintenance
. 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 accommodations
outside of the state highway right-of-way. Therefore, maintenance responsibility will
need to be determined as part of the discussions on the location of accommodation
with the local jurisdiction.
Pedestrian Accommodation Guidance
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.
Transit Accommodation Guidance
Transit service is recognized as an important component for providing an alternative
transportation choice for Iowans in both rural and urban areas, as well as a cost-
effective option for the transportation disadvantaged. One of the directives from Iowa in
Motion is to consider accommodations to support safe and convenient public
transportation. In response to that direction the following guidance has been developed
to implement the consideration of transit accommodation on the state highway system.
Development Guidance
The department will consider improvements that support safe and convenient public
transportation on state highway system construction projects as they are planned and
developed. In addition, the department will encourage Metropolitan Planning
Organizations and Regional Planning Affiliations to plan for transit accommodations in
their areas both on and off the state highway system. All transit accommodation will be
developed in cooperation with the local jurisdictions and transit providers.
. Safety: The safety of passengers, pedestrians, transit operators and motorists is of
the highest priority. All facilities shall be located so conflicts between pedestrians,
passengers and motorists in adjacent lanes are minimal. Curb and pavement
conditions shall be maintained in order to minimize hazards. Sidewalks to and from
bus stops shall be considered to accommodate the movement of transit riders.
. Pavement: Roadways and intersections with bus traffic and bus stops shall be
designed to accommodate the size, weight, and turning requirements of buses.
Roadway pavements and shoulders shall be of sufficient strength to accommodate
repetitive bus axle loads.
. Turnina Radius: At intersections that are turning points for buses, turning radii shall
be such that they provide safe and easy maneuverability of the buses that most
frequently use the road.
. Bus Bay (or turnout): A bus bay is a specially constructed area separated from the
travel lanes and off the normal section of a roadway that provides for the pick up
and discharge of passengers. This design allows for through traffic to flow freely
without the obstruction of stopped buses. Bus bays shall be considered at a
location when any of the following factors are present:
. Traffic in the curb lane exceeds 250 vehicles during the peak hours
. Posted traffic speed limit is greater than 35 mph
. Bus volumes are 5 or more per peak hour
. Passenger volumes exceed 20 boardings an hour
. Average peak period dwell time exceeds 30 seconds per bus
. History of traffic and/or pedestrian accidents at stop location
. Sight distances prevent traffic from stopping safely behind a stopped bus
. Shelters: Shelters provide protection from the elements and seating while
passengers wait for a bus. Standardized shelters exist that accommodate various
site demands and different passenger volumes. The location of shelters should
enhance the circulation patterns of patrons, reduce the amount of pedestrian
congestion at a stop, and reduce conflict with nearby pedestrian activities. The
need for shelters is usually subject to passenger boardings. The department will not
participate in the construction or maintenance of shelters.
The shelter will be located offset from the through traffic lane for the safety of the,
pedestrians in the shelter and the motorists. The distance of the offset will be
determined by the department in cooperation with the local jurisdictions and transit
providers.
. Bus Stop Location: Determining the proper location of bus stops involves choosing
among far-side intersection, near-side intersection, and mid-block stops. Each stop
location has unique advantages and disadvantages that must be reviewed by the
department, transit provider, and local jurisdiction. Some of the factors to be
considered when selecting the location of bus stops include the follOWing:
. Passenger protection from passing traffic
. Access for people with disabilities
. Proximity to major trip ge'lerators
. Street lighting
. Impact of the bus stop on adjacent properties
. Bus routing patterns (Le., individual bus movements at an intersection)
. Types of traffic signal controls
. Width of sidewalks
. Pedestrian activity through intersections
. Volumes and turning movements of other traffic
. Siqnalized Intersections: When signalized intersections are located near bus
stops, the timing of the signal and the potential use of advanced technology
systems shall be reviewed to determine if changes can be made to better facilitate
the flow of pedestrians.
. Park and Ride Lots: The department, in cooperation with Metropolitan Planning
Organizations and Regional Planning Affiliations, will identify needs and locations
for park and ride lots.
Implementation
Consideration of transit 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 not normally
be considered as part of a highway preservation improvement. Consideration of transit
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
accommodation (except bus shelter construction) is considered an additional highway
construction cost.
Providing transit 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.
CIN Rail/Highway Grade Separation Guidance
Legislation establishing the Commercial and Industrial Network (CIN) states that "the
purpose of this highway network shall be to improve the flow of commerce; to make
travel more convenient, safe, and efficient; and to better connect Iowa with regional,
national, and international markets." Consistent with this statement, Iowa in Motion
called for the evaluation of all CIN rail/highway at-grade crossings to determine the
need for. grade separations. Separations at CIN rail/highway crossings will benefit
Iowans by eliminating conflicts, reducing accidents, and improving operating efficiency
of both the railroad and the CIN. This section provides guidance on the evaluation and
implementation of CIN rail/highway grade separations.
Evaluation
To determine grade separation needs and priorities, the department will evaluate CIN
rail/highway at-grade crossings using factors listed below. The evaluation process does
not include CIN rail/highway crossings located on highways that will be bypassed in the
future. For example, a rail/highway crossing within a city that will be bypassed in two
years does not need to be evaluated because the CIN designation will move to the
bypass once it is constructed.
. Exposure Factor (product of existing average daily traffic and average number of
trains per day)
. Traffic volumes
. Truck volumes
. Rail traffic volumes (regular and seasonal)
. Accident rates
. Benefit vs. cost analysis
. Programmed and planned highway projects
. Land use
. Location constraints (e.g. topography)
. Future rail plans (potential for rail abandonment)
. Other factors as necessary
Implementation
Typically, CIN rail/highway crossings will be grade separated. In some cases grade
separation will not be required if the railroad line has been abandoned, abandonment
proceedings have begun, or factors are identified that make grade separation
impractical. In most cases, grade separations will be constructed in conjunction with
highway construction on new alignment or highway reconstruction. In some cases it
may be appropriate to develop grade separation projects independent of other highway
improvements.
Highway projects in the 1999-2003 Transportation Improvement Program with
programmed right of way and/or construction monies will not be modified to include
grade separations based on this guidance. Modifying programmed highway projects
would delay the improvement and add costs which cannot be funded without delaying
other projects.
If the evaluation shows that grade separation is impractical, alternative solutions will be
considered to accomplish the goals of this guidance. Possible alternative solutions
include construction of a highway bypass, relocation of the railroad, or addition of
Intelligent Transportation System (ITS) features (e.g.. installation of variable message
signs which redirect motor vehicle traffic to existing grade separations).
Bypass Guidance
The state highway system provides motor vehicles the means to travel to all regions of
Iowa, the Midwest, and the United States. The state highway system is stratified into
levels which describe the type of access provided: Interstate - national; Commercial and
Industrial Network (CIN) - Midwest; Area Development - statewide; Access Routes-
county wide; and Local Service - local. Because of the different types of service these
levels provide, the type of traffic on those levels varies significantly. For example, the
majority of traffic on the Interstate system is traveling long-distances in as little time as
possible. On the other end of the spectrum, the majority of traffic on Access Routes
and Local Service highways are merely traveling from community to community within a
county wide area.
On the Interstate system, full-access control is provided allowing traffic to move freely
on the system. Off the Interstate system, traffic on state highways may be impeded as
highways pass through communities because of traffic signals, stop signs, and
increased congestion. On higher level state highways, this impediment to traffic flow is
contrary to the service the highway is intended to provide to the majority of traffic using
the highway. This is especially true on the CIN.
The CIN was designated by the Transportation Commission as directed by the Iowa
Legislature. The legislature stated the goal of the CIN is to "improve the flow of
commerce; to make travel more convenient, safe, and efficient; and to better connect
Iowa with regional, national, and international markets." The construction of bypasses
on the CIN is an important activity to meet the legislatively directed goal of the CIN.
The following benefits of highway bypasses all contribute to meeting the goal of the
CIN:
. Safety improvements reduce injuries and deaths resulting from accidents
. Travel time is reduced for both people and goods
. Lower costs of production due to greater certainty of arrival time of inputs,
particularly in the case of just-in-time manufacturing
. Decrease in fuel and other vehicle operating costs
. Reduced noise and air pollution
. Reduced congestion within the bypassed community
Even though there are many benefits due to bypasses, the decision to construct a
bypass must be made carefully because of the construction costs and the economic
and social impacts on the bypassed community. This guidance describes the factors
used in the evaluation to determine the need to bypass a community.
Evaluation
The impacts of a bypass can vary significantly from community to community. To
identify these impacts it is important that an evaluation be conducted in each case.
This is also important because the varying impacts and circumstances make it difficult
to provide specific rules on when bypasses should or should not be built. As bypass
needs are evaluated, local residents and communities will be consulted and asked to
provide input in the decision making process. When determining the need to bypass a
community, the department will evaluate the following factors:
. Planning Classification of the Highway
. Interstate: The Interstate is required to have full-access control, therefore
bypasses are not an issue on this system.
. Commercial and Industrial Network (CIN): As described earlier in the guidance,
the free flow of traffic on this level is important due to the type of traffic that is
served and to meet the legislatively directed goals of the CIN. Therefore,
bypasses have been found to be beneficial.
. Area Development: This level serves traffic that is traveling to and from different
regions of the state. In some instances, the predominant traffic on an Area
Development highway may benefit from a bypass.
. Access Routes: Highways on this level typically will not benefit from bypasses as
the traffic is traveling short distances.
. Local Service: Bypasses will not be constructed on Local Service routes due to
the short intra-county trips associated with these highway.
. Amount of Through Traffic
The benefits of a bypass increase as the number of vehicles that pass through a
community increases. A bypass allows these vehicles to make the trip without
driving through the community. This reduces congestion in the community, the
number of accidents, travel time, and vehicle operating costs. In addition to total
through traffic, the mix of through traffic (I.e. automobiles vs. trucks) is also
important because of impacts on congestion, noise, and air pollution.
. Corridor Design
. Four-Lane: Corridors that are four-lane or are to be built as four-lane facilities will
typically benefit from the construction of bypasses. This is due to the amount of
traffic on the facility and driver expectation of free flow. Four-lane corridors on the
CIN will typically bypass communities with full access control.
. SUDer-2: Corridors that are Super-2 or will be built as Super-2 facilities may not
require bypasses of communities. Because Super-2 highways are the minimum
standard for the CIN regardless of traffic levels and because Super-2 highways
are being built on the Area Development level, the need for a bypass is not as
clear as it might be on a four-lane corridor. Therefore, the consideration of the
other factors is more important in the evaluation. In cases where a community is
not bypassed on a super-2 corridor, a higher level of access control may be
needed to assure the benefits of a super-2 highway are preserved.
. Two-Lane: Two-lane corridors typically would not require bypasses of any
community.
. Land Use Plans
Community and county land use plans will be reviewed to identify development
plans in the area and the impacts that could result from construction of a bypass.
. User Benefits
An evaluation of the user benefits associated with the bypass will be conducted.
This will provide a measure of the accident reduction, travel time reduction, and
vehicle operating cost savings of constructing a bypass that can be compared with
the cost of constructing a bypass.