What is ITD?

The Idaho Transportation Department is committed to providing high quality, cost-effective transportation systems that are safe, reliable and responsive for the economical and efficient movement of people and products.

Idaho 's transportation system is an integrated network of more than 60,000 miles of roads, about 4,000 bridges, 1,887 miles of rail lines, 125 public airports, and the Port of Lewiston . Of these, the transportation department has jurisdictional responsibility for almost 5,000 miles of highway (or nearly 12,000 lane miles), more than 1,700 bridges, and 30 recreational and emergency airstrips. Also included on the state highway system are 30 rest areas and 10 fixed ports of entry.

The transportation department also oversees federal grants to 15 rural and urban public transportation systems, provides state rail planning and rail-project development and supports bicycle and pedestrian projects.

How is ITD organized?
More than 1,800 employees statewide carry out the transportation department's commitment to provide safe, efficient travel. They are located in virtually every part of Idaho , from headquarters in Boise to ports of entry at Idaho 's borders and maintenance buildings on rural highways.

The department is divided into six divisions: Aeronautics, Highways, Motor Vehicles, Transportation Planning, Administrative Services and Public Transportation. Three support offices — Budget Policy and Intergovernmental Relations, Internal Review and Office of Communications— complement those divisions and are instrumental in delivering the department's services.


How can I find out about road conditions in my area?

The 511 travel information service gives updates on winter road and weather conditions, emergency closures and access to tourist information 24-hours-a-day, seven-days-a-week.

By dialing 511 or visiting on the Web, travelers are updated as conditions change on Idaho's highways and provided timely and accurate information.  

Type of information available include weather-related road conditions, traffic incidents and delays, emergency road closures, highway construction projects (coming in Spring 2006) and tourism information.

511 expands and improves what was formerly the Idaho Road Report.


How does ITD decide where a stoplight should be installed?

Stoplights are designed to ensure a safe and orderly flow of traffic. They provide safety for pedestrians and vehicles while crossing a busy intersection. Lights allow motorists to “take turns” when traveling through busy intersections and in the right locations. They can enhance both safety and efficiency for pedestrians and traffic.

In the wrong location, however, a stoplight can create numerous unnecessary hazards such as delays, congestion, and accidents.

The Idaho Transportation Department strives to find those locations where a light will help more than it will hinder. The purpose of stoplights is to relieve more congestion than they will cause. In every case, the safety of Idaho motorists is ITD's primary consideration.

ITD works in conjunction with federal guidelines that establish minimum conditions under which a light installation can be considered. Traffic engineers assess whether or not a light is a proper means of traffic control by carefully assessing the intersection's use by vehicles and pedestrians. The transportation department looks at the physical make-up of the intersection, roadside development and delays experienced by motorists during peak hours. ITD also considers average vehicle speed, the number and types of accidents that occur and future road construction plans.

What are the advantages of a stoplight?
Stoplights provide the maximum degree of control at intersections. They relay messages of both what to do and what not to do. Their primary function is to assign right-of-way to conflicting movements of traffic at an intersection. They do this by permitting conflicting streams of traffic to share the same intersections by means of time separation.

In some cases lights can contribute to safer driving conditions. This is most common at intersections where accidents involving vehicles approaching from different directions occur at an abnormally high frequency and other remedies to prevent these accidents prove unsatisfactory.
What are the disadvantages of a stoplight?
Stoplights in the wrong location can actually contribute to the problems they were meant to alleviate. Misplaced signals increase rear end accidents and in some cases, angle collisions still occur at signalized intersections when motorists run red lights.

Stoplights can also create unnecessary travel on alternate routes and a more congested traffic flow. They can also create excessive delays, which in turn increase driver aggravation and encourage motorists to disobey signals. This problem is increased when stoplights are placed too close to each other. On an average State Highway , where signals are placed one-half of a mile apart, a driver can maintain an average speed of 36 mph. When the signals are spaced one-quarter of a mile from each other, the maximum average speed a driver can maintain drops to 18 mph.
What are alternative solutions to a stoplight?
Many accidents at intersections are not caused by the absence of a stoplight: inattentive driving, drunk drivers, and speeding are common contributors. Other traffic control devices that might prove safer include turning lanes, warning signs, improved roadway lighting, and pedestrian crosswalks.
How do stoplights work?
There are two different types of stoplights in Idaho : fixed time and traffic response. Fixed time stoplights assign the green light to the different approaches of an intersection for a predetermined amount of time. Some can also be set to different lengths of green time during peak traffic hours. These types of signals are typically found in urban areas where traffic movement is fairly predictable.

Traffic responsive signals change the lights according to the amount of traffic in each direction. These signals use sensors to detect the amount of vehicles and automatically adjust the length of the green time. This allows as many vehicles as possible through the intersection before responding to the presence of vehicles approaching from another direction.


How are speed limits set?

Speed limits are intended to supplement the drivers' judgment in determining what is a reasonable speed for particular road and weather conditions. Limits are imposed to assist Idaho law enforcement. They encourage better traffic flow by reducing the variances in speed.

Traffic limits that reflect the behavior of the majority of motorists are found to be successful. Laws that arbitrarily restrict the majority of drivers encourage wholesale violations, lack public support, and generally fail to produce desirable changes in driving behavior.

In accordance with federal guidelines, ITD uses the 85th percentile speed of free flowing traffic for determining a safe and reasonable speed for a given road section. Traffic Engineers set the limit at the speed at which 85 percent of the traffic is driving. This reflects the safe speed as determined by a large majority of drivers.

According to research, accident involvement is the lowest within that 85 percent. Speed limits are also determined by a combination of two investigations involving engineering and traffic:

  • The engineering investigation involves determining the design of the road and its immediate environment. Engineers analyze such items as lane width, pavement type and condition of the road. They also look at terrain, parking conditions, residential development along the road and the number, width and types of entrances and intersecting streets.
  • The traffic investigation involves gathering and analyzing traffic related data such as traffic volumes, accident frequency, and the effect of traffic control devices such as stoplights and stop signs.

  • After all variables have been considered and a speed limit is established, traffic should flow at a safe and efficient level.

    Does reducing a speed limit result in safer driving conditions?
    Not necessarily. Reducing the limit below the warranted speed can actually be hazardous and unsafe. Studies have shown that merely reducing a speed limit has little effect on the speed at which motorists will travel. Furthermore, no published research findings have established any direct relationship between posted speed limits and accident frequency.

    When determining speed limits, engineers attempt to set a realistic limit that the majority of drivers will obey and that can be reasonably enforced.


    What safety seat is right for my child?


    What is the gas tax?

    Gasoline and special fuel taxes are collected by the Idaho Tax Commission and are deposited into the Highway Distribution Account. Idaho 's fuel tax is 25 cents a gallon. Similarly, taxes on special fuels, such as diesel and propane, also are deposited into the HAD. The gas tax helps fund road and street jurisdictions, including all state, county, highway district and city jurisdictions.


    How is Idaho's transportation system paid for?

    Funding comes from federal, state and local taxes, and fees. Funding is driven by the department's strategic plan, based on projected federal and state revenues and appropriations by the Idaho Legislature. The available revenues are allocated to six major areas: highways, motor vehicles, planning, aeronautics, public transportation and management support.

    The major source of state funds for all road and street jurisdictions (state, county, highway district and city) is the Highway Distribution Account (HDA). Funds deposited into the account are collected from a number of sources and are distributed according to Idaho law. The funding sources for the highway distribution account are:
    1. Gasoline and special fuel taxes: These taxes are collected by the Idaho Tax Commission and are deposited into the HDA. Idaho 's fuel tax is 25 cents a gallon. Similarly, taxes on special fuels, such as diesel and propane, also are deposited into the HDA.
    2. Vehicle registrations: Another major source of revenue to the HDA is vehicle registrations. The registration fee for passenger cars is based on the age of the vehicle.
    3. Truck registrations: Trucks weighing 8,000 to 60,000 pounds gross vehicle weight pay registration based on weight group and type of operation. Trucks with more than 60,000 pounds gross vehicle weight pay a single registration fee calculated by truck weight and mileage group. These funds also are deposited into the HDA.
    4. Miscellaneous fees: Other HDA fees are derived from license plate fees (including personalized and specialty plates), driver licenses and fines. Combined, these fees represent a small percentage of the total account.
    State highway account funds projects
    Revenue from the HDA for the maintenance, repair and construction of Idaho 's 5,000-mile state system is deposited into the state highway account for transportation department use. The department receives approximately 56 percent of the HDA revenue after the deductions are made. The remaining amount is divided among city, county and highway district jurisdictions and the Idaho State Police. Revenue from sources such as permits and licenses is deposited directly into the state highway account for use by the transportation department. Those “other funds” represent approximately 10-12 percent of the total state revenue deposited into the state highway account.
    Federal funds are critical
    The other major funding source for Idaho highways is the Federal Highway Trust Fund. Those funds are authorized to Idaho for highway construction, planning, safety and other uses on a project-by-project basis.
    Authorized funds are subject to caps and “holdbacks” at the federal level. Idaho is authorized to spend a percentage of its allocated funds every fiscal year. Major funding categories include: national highway system, surface transportation program, interstate maintenance, emergency relief, forest highways, bridges, congestion mitigation and air quality, and transportation enhancements.
    Other sources provide funding to promote public safety campaigns, build recreational trails and improve scenic byways.


    How are decisions made?

    Highways, aviation, rail and public transportation needs are considered when shaping Idaho 's transportation future. The transportation department recognizes and values the needs of a truly intermodal society, whether it involves improving at-grade railroad crossings, reconstructing freeway interchanges, repairing bridges, building bicycle and pedestrian paths, improving backcountry airstrips or resurfacing highways.
    The department's planning specialists work closely with state leaders, local governments, private commerce and individuals to ensure a responsive, efficient partnership.

    How is the public involved?
    Because Idaho 's transportation system belongs to the public, shared involvement in planning, developing and maintaining all facets of transportation is essential. That is the foundation upon which the transportation department's public involvement program is based. Construction and maintenance programs reflect needs that emerge from the grassroots of Idaho . Public input is essential in locating interchanges, widening travel lanes, resurfacing roadways, determining traffic patterns and creating pedestrian and bicycle paths.

    The public involvement process includes both talking and listening, teaching and learning. While projects are not expected to be unanimously endorsed by every citizen, the transportation department is committed to the two-way information exchange as an indispensable part of a representative decision- making process. These decisions balance the need for safe and efficient transportation with the need to preserve economic, social and environmental conditions. The transportation department strives to be not only a good provider, but a good neighbor as well. Project planning includes numerous opportunities for the public to convey needs and suggestions. Those lines of communication instill shared ownership and a common vision for Idaho 's transportation system. Information meetings and formal hearings provide public access to the process. By encouraging public involvement early and often in the planning and development of transportation projects, the department hopes to ensure a product that serves the best interests of the most people.
    Who makes the decisions?
    The seven-member Idaho Transportation Board meets monthly to receive input from the public and administrative staff members. The board establishes state transportation policy and guides the planning, development and management of a complex statewide transportation network. It is responsible for assuring Idahoans a safe and efficient system that enhances the economy and quality of life. To ensure widespread opportunities for public input, the board usually meets six times a year in Boise and once in each of the six districts.

    The governor appoints transportation board members, who then are confirmed by the Idaho Senate. Six members represent and live in each of the administrative districts; the seventh member of the citizen board is selected by the governor to serve as chairman.

    Six of the seven board members are appointed to six-year terms, beginning Jan. 31. Their terms are staggered, enabling one appointment each year. The seventh member, the chairman, serves at the pleasure of the governor, conducts the monthly meetings and votes on motions only in the event of a tie. No more than four members may be of the same political party.


    How are construction projects chosen?

    The Idaho Transportation Department's construction itinerary begins with the Statewide Transportation Improvement Program (STIP), a five-year master plan. The STIP identifies projects that have been selected through an inclusive and ongoing process. It represents the vision of the department's board and director, elected officials from throughout Idaho , user groups and concerned citizens, all of whom share in shaping the plan.

    The STIP establishes schedules for a variety of projects, including:

    1. Highway, bridge, bicycle and pedestrian facilities
    2. Highway safety
    3. Air quality
    4. Railroad crossing safety
    5. Airports
    6. Public transportation
    7. Transportation planning
    8. A number of grant programs

    Partnerships within the public and private sectors will continue to strengthen the department's planning efforts.
    As the foundational tool for shaping future construction, the STIP also depends on public participation. Input is encouraged before the annual updated plan is presented to the transportation board for approval.


    Can I hang an election poster along a state highway?

    Putting election posters on utility poles, trees, rocks or on temporary stakes within a highway right of way is prohibited. Election posters may be affixed to privately owned fences bordering the right of way, subject to local zoning ordinances, providing the owner grants permission and no portion of the poster protrudes onto public property. All unauthorized posters are subject to removal. The transportation department removes posters or signs when they obstruct a motorist's view or are a distraction.


    What is Idaho's Quick Clearance Law?

    “Quick Clearance” is the law in Idaho as of July 1, 2005. The legislation is designed to improve safety and traffic flow on the state's interstates and major divided highways. If you are involved in a crash on one of these roadways that does not cause a death or injury, and you are able to safely drive your vehicle out of travel lanes, you are required to do so.

    Why is this law important?

    Some collisions occur as the result of another crash. In some cases, emergency responders are victims in these secondary crashes. Clearing the road following a crash and giving emergency responders plenty of room reduces the chance that another collision will occur.

    For every minute a roadway lane is closed, it takes several minutes for traffic to recover. Closed travel lanes cause significant congestion and cost Idaho businesses and employees in missed work time, additional business expenses and increased fuel consumption.

    What should I do if I am involved in a crash?

    The law only applies to interstates and major divided highways. Signs along these roadways help clarify where the law applies. If you are on an interstate or major divided highway, move your vehicle to a shoulder, median or emergency lane if you can safely do so and the crash did not cause a death or injury. You should do this whether or not a law enforcement officer is on the scene. If an officer is present and directs you otherwise, always follow the officer's instructions.

    Will I be liable if I move my vehicle before the crash is investigated?

    No one will be considered at fault for the cause of a collision, solely because they moved a vehicle in accordance with Idaho's Quick Clearance Law.

    How will this law impact law enforcement investigations?

    The Quick Clearance Law will not interfere with any law enforcement officer's duty to investigate crashes or enforce criminal, traffic or highway laws. However, it does give officers the authority to require removal of vehicles or debris from freeway travel lanes. The Idaho Transportation Department's Incident Response crews assist law enforcement in clearing crash scenes along the busy Interstate in the Treasure Valley .

    Idaho 's Quick clearance Law is sponsored by the Idaho Transportation Department and Idaho State Police.


    What is access management?

    Access management is the process of balancing the need for traffic movement with property access.

    Roads serve two primary purposes; to provide mobility and access. Mobility is the efficient movement of people and goods. Access is getting those people and goods to specific properties. A roadway designed to maximize mobility typically does so in part by managing access to adjacent properties.

    Most state highways serve a function somewhere between interstate highways, which have very limited access and high mobility, and local residential roads, which provide numerous accesses to properties but are not appropriate for long distance travel. One of the Idaho Transportation Department´s (ITD) most important responsibilities is to ensure that the design of each state highway properly balances access and mobility. Access management is the tool used to provide this balance.

    How does access management improve safety?
    Between 2000 and 2004, more than 17% of Idaho´s non-interstate crashes were related to access movements. ITD access standards aim to provide the optimal balance between access and mobility by reducing points of traffic conflict. Conflict points are locations on a roadway where two vehicles can potentially cross paths. At a four-way intersection there are as many as 32 conflict points, each representing the location of a possible crash. Drivers can be overwhelmed by large amounts of conflict points, increasing the potential for accidents. Good access management strives to separate conflict points by providing a reasonable distance between driveways and median openings, and restricting certain movements at some median openings.

    Poor access management compromises the safety and efficiency of the highway and can result in increased accidents, commute times, vehicle emissions and fuel consumption.

    Will access management hurt my business?
    ITD recognizes the time and money investment business owners put into establishing and growing their business. Both successful businesses and a safe and efficient highway system are crucial ingredients for the economic prosperity of our state.

    The movements that occur at driveway locations can make it difficult for through traffic to flow smoothly at desired speeds when those driveways are too closely spaced. Through access management, traffic flow becomes efficient and congestion decreases, resulting in increased exposure to roadside businesses. This can also delay the need to widen a road for several years.

    Even in situations where the implementation of access management creates a slightly longer route for customers to get to a business, national studies have found that customers have no problem driving a greater distance, including negotiating U-turns, to access a "destination" business (specialty retail stores, service-oriented businesses). In the case of "pass-by" businesses (gas stations, fast-food restaurants, etc.), studies have shown that as long as reasonable access is provided, access management modifications have little effect on their success.

    Poor access management hurts businesses by creating congested, high accident roadways. Closely spaced and poorly designed driveways make it more difficult for customers to enter and exit businesses safely, and access to corner businesses may be blocked by backed up traffic. Newer businesses will seek out locations that have fewer access and congestion problems, and customers will patronize businesses with safer, more convenient access.

    How can I be involved in developing my access future?
    ITD encourages and seeks public input for roadway planning projects. Access management is always an important part of these discussions. Opportunities to give input for projects are publicized through the media, newspaper advertisements and direct mailings. We encourage you to get involved!

    Anyone concerned with access management may also contact their ITD district office. Questions and comments are always welcome.


    Why is the transportation department involved with outdoor advertising?

    As part of the Highway Beautification Act, Federal Law requires the department to provide continuing, effective control of outdoor advertising. We do this by requiring signs placed within federally designated routes to meet size and placement criteria, which vary depending on the location of each sign. For more information on outdoor advertising requirements, click here.