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Traffic signs, while often considered peripheral design elements, play a critical role in communicating a variety of information to users of the transportation system. Signs are used to guide, warn, regulate, and convey information to vehicular and pedestrian traffic along the roadway.

The Manual on Uniform Traffic Control Device (MUTCD) provides guidance on the design and placement of signs, including the size of the sign and text, placement along the roadway, and standard information to be conveyed. Most states, including Missouri, use the MUTCD as the primary guide for developing roadway signage. Some states, such as Illinois, provide supplemental guidance that builds upon the information in the MUTCD. Engineers and contractors also use standard drawings, similar to those provided by the Missouri DOT, to ensure that signs are designed and constructed appropriately.

Traffic signs are often one of many traffic control devices that users must process while navigating streets. Therefore, it is important to design and position signs in a manner that ensures that users have enough information to safely and efficiently navigate the street network without becoming distracted or overwhelmed.

Washington Avenue sign
Credit: CH2M HILL

The MUTCD specifications help ensure a minimum level of uniformity among traffic signs nationwide. Uniformity is a critical component of effective traffic sign communication, as users are better able to recognize and respond to familiar signs. Although some jurisdictions may wish to modify the standard sign types to be more attractive, the majority of traffic signs are required to conform to the MUTCD specifications. One exception is street name signs, which may be customized and used to help create a theme or identity for a place. Many agencies are developing artistic street signs, such as the Washington Avenue sign in downtown St. Louis shown at right, to add character to the streetscape.

The ITE Traffic Handbook indicates that traffic control devices, including traffic signs, should:

  • Meet a need
  • Command attention
  • Convey a clear and simple meaning
  • Command respect of the road users
  • Give adequate time for proper response/reaction

Characteristics that influence signing for residential thoroughfares:

  • Significant pedestrian presence
  • Slower speeds
  • Numerous parking regulations

Pedestrian presence requires effective communication to vehicular traffic.  For residential streets to be great, pedestrians must feel safe from and respected by the adjacent vehicular traffic.  Traffic signs are one way to nurture this relationship.  Appropriate signage in advance of intersections and mid-block crosswalks are important to alert drivers of potential pedestrian crossing locations.  These signs might be installed with flashing lights to better command driver attention.  Enforcement is also important to make sure that the signs are abided by.  Enforcement of pedestrians to limit jay-walking and other improper street crossing is equally important.

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Mid-block crossings are important elements along residential thoroughfares. The picture at right depicts a great example of actuated mid-block pedestrian crossing signs. When a pedestrian presses the button below the sign, the lights on the sign begin to flash, signaling the oncoming traffic to stop. This treatment goes beyond our typical signage to place greater emphasis on the pedestrian.  In addition to the sign, special pavement markings are placed in advance of the crosswalk to represent the "yield line" at which vehicles are to stop when the signs begin to flash. 

This additional provision provides a buffer zone between the crosswalk and the vehicular traffic, aiding the pedestrian's effort to visually confirm that oncoming traffic has come to a stop. Just as traffic signs are important to control and direct vehicular traffic, pedestrian-scale signing is equally important along small town downtown streets.

Signing should also be used to clearly communicate the presence of multi-modal uses and services along the street.  If bicycles are common along the corridor, appropriate “Share the Road” signs should be strategically placed along the street as a reminder to drivers. 

But again, we must go beyond the mere accommodation of other modes such as bicycles; we must prioritize them.  Signing is just one of many ways to accomplish such a prioritization.  The photo at right demonstrates a simple sign treatment at an intersection.  The sign prohibits right turns to vehicular traffic, but "excepts" bicycles.  It's a simple but effective way to prioritize bicyclists and raise driver awareness to bicycle presence along the street. 

Way-finding signs help to effectively guide and inform the numerous pedestrians along the street. These pedestrian-scale signs place a priority on pedestrian travel along the thoroughfare, and they can also visually enhance the streetscape. Way-finding signs can be particularly useful in directing (and encouraging) pedestrians to transit connections nearby. They provide a subtle reminder to residents that there are other mode choices available to them.

Residential neighborhoods will often have children playing in the yards and other open areas abutting the street.  There are signs that can be posted to warn drivers of such presence, thus making drivers better prepared to stop in the event of a child that may inadvertently stray into the travel way of the road.  In addition to children at play, bicyclists and dog-walking pedestrians are also common within residential place types.  Appropriate signage can make drivers more aware of the active pedestrian environment through which they are driving.

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Slower speeds in residential place types make it easier for drivers to process information provided by traffic signs.  One of the challenges, though, is keeping the speeds low.  It is not uncommon for through-traffic on residential streets (especially those that are part of the arterial network) to drive above the speed limit in an effort to minimize travel time.  Speed limit signs should be diplayed intermittently along the street to remind drivers of the lower speed limit.  Speed limit signs alone, though, are not sufficient enough to maintain the desired low speed of travel.  Enforcement is an effective measure, but it is costly to have continuous enforcement.  Studies have shown that when enforcement measures are removed, vehicles typically resume their higher speed of travel.  One measure that has proven to be effective in Minnesota is to use speed limit signs in conjunction with radar speed measurement displays <see PDF>.  While not appropriate in all locations, they have proven to be particularly beneficial in areas that are plagued by travel speeds exceeding the speed limit.

Trees, bushes, and other large landscaping features are not uncommon along residential streets.  Effective sign placement should consider how such features might obstruct the sign from driver view.  Homeowners and street maintenance departments should be vigilant about maintaining the reach of tree branches and bushes to insure that they do not interfere with traffic sign visibility.  A "Children Playing" sign will do no good if it is hidden from view by a maturing tree branch. Consider how new vegetation might impact signing once the vegetation is fully matured, not just when it is initially planted.

The types of drivers expected to be present in residential neighborhoods should be considered when planning and designing signing along the street.  With ever-increasing life expectancies, drivers are older than they once were.  Recent research suggests such drivers have difficulty reading smaller signs. Special consideration of sign size and text/font size for signs should reflect this, especially in neighborhoods of high elderly population.