The Institute of Transportation Engineers, an international professional organization, defines traffic engineering as “that phase of engineering which deals with the planning, geometric design and traffic operations of roads, streets and highways -- their networks, terminals, abutting lands and relationships with other modes of transportation – for the achievement of safe, efficient and convenient movement of persons and goods.”

Below you will find the Neighborhood Traffic Control Program document. This document will outline the process required to request speed humps and the steps that must be taken before speed humps can be installed. A flow chart and sample petition documents have also been provided for your convenience.

Traffic Control Program

Speed Hump Flowchart

Speed Hump Petition

While there are some advantages of speed humps, such as, the generally decrease speeds if placed strategically and may divert traffic to main streets, away from residential areas, there are also a number of disadvantages. Speed humps may result in a slower response time of emergency vehicles, they increase noise levels due to engine and brake noise, and can also cause higher speeds in between speed humps, as some drivers will try to compensate for lost time.

When traffic goes too fast on a street, people sometimes suggest we install speed humps to slow vehicles down. The use of speed humps typically lower vehicle speeds to about 15 miles per hour. Speed humps can be installed on some local roads when a speeding issue has been documented, the geometry of the roadway allows, and a majority of the effected property owners are in favor of the speed humps. For more information see the Neighborhood Traffic Control Program document.

Below you will find the Neighborhood Traffic Control Program document. This document will outline the process required to request a stop sign and the steps that must be taken before a stop sign can be installed. A flow chart and sample petition documents have also been provided for your convenience.

Traffic Control Program

Stop Sign Flowchart

Stop Sign Petition

The City uses the Manual for Uniform Traffic Control Devices to determine if a stop sign is warranted. In most cases, a two-way stop sign is sufficient to define who has the right-of-way. A four-way or all-way stop is considered an option only when an intersection with an existing two-way stop is the site of numerous crashes or is experiencing a significant traffic congestion problem. In general, the criteria for four-way all-way stops are:

• Five or more crashes have occurred over a 12-month period that are correctable by a four-way stop sign.
• The vehicular volume entering the intersection from the major street approaches averages at least 300 vehicles per hour for any eight hours of an average day; and
  • The combined vehicular, pedestrian, and bicycle volume from the minor street approaches averages at least 200 units per hour for the same eight hours, with an average delay to minor street vehicular traffic of at least 30 seconds per vehicle during the highest hour.
  • If the 85^th percentile approach speed of the major street traffic exceeds 40 mph, the minimum vehicular volume warrants are 70 percent in the above requirements.

The City uses the Manual for Uniform Traffic Control Devices to determine if a stop sign is warranted (see question regarding stop sign warrants criteria). Once the need for a stop sign is established, the City Engineer works alongside the Public Works Department to make the final determination on the placement of stop signs after considering the following: traffic flow, volume, intersection configuration, and traffic accident reports.

The City regularly receives requests from residents to install stop signs as a speed control measure. Several studies have shown that using stop signs to control speeding does not bring about the desired results. When stop signs are used to slow speeding, drivers tend to increase their speed between signs or intersections to compensate for lost time due to stopping at the stop sign. Studies also indicate that some drivers will accelerate rapidly after a stop, which exacerbates already unsafe conditions.

Too many stop signs can cause motorists to ignore the right-of-way rule or just plain ignore the stop sign itself. Placing stop signs in a neighborhood can also result in increased levels of pollution and noise. It also can cause adverse impacts on nearby streets since many drivers will seek new routes to avoid the stop signs. This can lead to new traffic problems and complaints in adjacent neighborhoods.

Justifying the installation of a traffic signal requires considerable data collection and analysis. The following data must be collected and analyzed:

• Traffic volumes by approach and movement during 12 hours of an average day

 • Pedestrian counts in crosswalks

 • Information on nearby facilities and activity centers that serve the young, elderly, and/or disabled

• Posted or statutory speed limits or the 85th percentile speeds on the uncontrolled approaches

• Collision diagrams of recent crashes

• Condition diagram of the intersection

The MUTCD lists nine warrants for the placement of traffic signals, as summarized below (please refer to Chapter 4C of the MUTCD for details): 

1. Eight-hour vehicular volume. The volume of intersecting traffic is sufficiently high to consider installing a traffic control signal, or the traffic volume on a major street is so heavy that traffic on a minor intersecting street suffers excessive delay or conflict in entering or crossing the major street.

2. Four-hour vehicular volume. The volume of intersecting traffic is sufficiently high to consider installing a traffic control signal.

3. Peak hour volume. Traffic conditions are such that for a minimum of one hour of an average day, the minor street traffic suffers undue delay when entering or crossing the major street.

4. Pedestrian volume. Traffic volume on a major street is so heavy that pedestrians experience excessive delay in crossing the major street.

5. School crossing. The frequency and adequacy of gaps in the traffic flow are insufficient for schoolchildren crossing the major street.

6. Coordinated signal system. The installation of a traffic signal as part of a coordinated signal system at an unsignalized intersection would provide progressive movement and maintain vehicle platooning.

7.  Crash experience. Other alternatives do not decrease crashes, and the severity and frequency of crashes are correctable by use of a traffic signal. 

8. Roadway network. A signal installation would encourage traffic flow concentration and organization on the roadway network.

9. Intersection near a grade crossing. An intersection approach controlled by a stop or yield sign is in close proximity to a railroad grade crossing.

If none of these warrants are met, a traffic signal should not be installed. In addition, the fulfillment of a warrant or warrants does not in itself justify the installation of a signal.

Installing a traffic signal at a low-volume intersection can significantly increase delays and crashes. The length of delay is directly related to a number of factors. For example, one factor is cycle length, which is influenced by traffic volumes and the need to safely accommodate pedestrian crossing times. As noted above, the increase in delay and stops then translates into higher fuel consumption, increased travel times, and higher point source emissions. Additionally, although traffic signals can reduce the total number of crashes at an intersection, research has shown that certain types of crashes (e.g., rear-end collisions) may actually increase after a signal is installed. For this reason, the type and number of crashes at an intersection should be considered before the installation of a traffic signal.

Installing traffic control devices such as stop signs or traffic signals where they are not needed can significantly disrupt traffic flow and increase intersection delay for drivers. The induced delay increases travel time and frustrates drives, and the additional stops and starts result in increased full consumption and the consequent production of vehicle emissions.

People often believe that posting a lower speed limit will force drivers to slow down and will result in fewer traffic crashes, but that’s not always true. Although crashes at high speeds can result in more severe injuries, research has found that higher speed limits do not necessarily result in more crashes. One principle that helps determine a speed limit is that the safest situation on a roadway is when all vehicles are traveling at about the same speed. When a speed limit is set unreasonably low, some drivers tend to ignore the signs. Other drivers will try to obey the posted speed limit. The result is that the roadway is carrying both fast-moving and slow-moving vehicles, which is the perfect recipe for a crash. Speed limits changes can be made, however, by determining the 85^th percentile speed. If the 85^th percentile speed is 5mph over or over the posted limit, the speed can be changed to reflect the 85^th percentile speed.

The 85^th percentile speed defines the speed that 85 percent of drivers will drive at or below under free-flowing conditions. The 85^th percentile is determined by completing a speed study. A speed study will track the speeds of all vehicles over a given period of time.

Posting speed limits lower than the 85^th percentile speed does not result in voluntary motorist compliance with the posted speed limit unless there is strict, continuous, and visible enforcement. Increased enforcement is effective only at the immediate time and in the area where the police officer is present.

Below you will find the Neighborhood Parking Control Program document. This document will outline the process required to request parking restrictions and the steps that must be taken before parking restrictions can be implemented. A flow chart and sample petition documents have also been provided for your convenience.

Neighborhood Parking Control Program

Parking Control Flowchart

Parking Control Petition

When a new or substantially improved development application is submitted, the City’s Engineering Department will determine whether a Transportation Impact Study is required. A study will be required for all residential subdivisions containing more than 200 lots, non-residential subdivisions containing 50,000 square feet of floor area, or at the discretion of the Community Development Director and City Engineer.

The Transportation Impact Study guidelines can be found in the document linked below:

Transportation Impact Study Guidelines Document