Traffic calming uses physical design and other measures to improve safety for motorists, pedestrians and cyclists. It has become a tool to combat speeding and other unsafe behaviours of drivers in the neighbourhoods. [1] It aims to encourage safer, more responsible driving and potentially reduce traffic flow. Urban planners and traffic engineers have many strategies for traffic calming, including narrowed roads and speed humps. Such measures are common in Australia and Europe (especially Northern Europe), but less so in North America. Traffic calming is a calque (literal translation) of the German word Verkehrsberuhigung– the term's first published use in English was in 1985 by Carmen Hass-Klau. [2]
In its early development in the UK in the 1930s, traffic calming was based on the idea that residential areas should be protected from through-traffic. Subsequently, it became valued for its ability to improve pedestrian safety and reduce noise and air pollution from traffic.[ citation needed ]
For much of the 20th century, streets were designed by engineers who were charged only with ensuring smooth motor vehicular traffic flow and not with fostering the other functions of streets. Traffic calming initiatives have grown to consider other design functions as well. For example, it has been shown that car traffic severely impairs the social and recreational functions of public streets. The Livable Streets study by Donald Appleyard (1981) [3] found that residents of streets with light traffic had, on average, three more friends and twice as many acquaintances as the people on streets with heavy traffic which were otherwise similar in dimensions, income, etc.[ citation needed ]
Traffic engineers refer to three "E's" when discussing traffic calming: engineering, (community) education, and (police) enforcement. Because neighborhood traffic management studies have shown that residents often contribute to the perceived speeding problem within their neighborhoods, instructions on traffic calming (for example in Hass-Klau et al., 1992 [4] ) stress that the most effective traffic calming plans entail all three components—that engineering measures alone will not produce satisfactory results.
Engineering measures involve physically altering the road layout or appearance to actively or passively reduce traffic speeds by one of several means:
Measures include speed humps, chicanes, curb extensions, modal filters, and living street and shared space type schemes. The town of Hilden in Germany has achieved a rate of 24% of trips being on two wheels, mainly via traffic calming and the use of 30 km/h or 20 mph zones. [5] In 1999, the Netherlands had over 6000 woonerven where cyclists and pedestrians have legal priority over cars and where a motorised "walking speed" limit applies. [6] However, some UK and Irish "traffic calming" schemes, particularly involving road narrowings, are viewed as extremely hostile and have been implicated directly in death and injury to cyclists and pedestrians. [7] [8]
A number of visual changes to roads are being made to encourage more attentive driving, reduced speed, reduced crashes, and a greater tendency to yield to pedestrians. Visual traffic calming includes lane narrowings (9–10'), road diets (reduction in lanes), use of trees next to streets, on-street parking, and buildings placed in urban fashion close to streets.
Physical devices include speed humps, speed cushions and speed tables, sized for the desired speed. Such measures normally slow cars to between 10 and 25 miles per hour (16 and 40 km/h). Most devices are made of asphalt or concrete but rubber traffic calming products are emerging as an effective alternative with several advantages.
Traffic calming can include the following engineering measures, grouped by similarity of method: [9]
Quite often residents have used a variety of homemade devices ranging from faux enforcement camera signs and even faux speed cameras and including dummy police. Some Canadian communities erect flexible bollards in the middle of the street in school zones. The bollards have a sign affixed indicating a 40 km/h speed limit.
There are primarily two implementation options for the creation of traffic calming measure: capital reconstruction versus operational changes.[ citation needed ]
Enforcement and education measures for traffic calming include:
Speed reduction has traditionally been attempted by the introduction of statutory speed limits. Traffic speeds of 30 km/h (20 mph) and lower are said to be more desirable on urban roads with mixed traffic. [13] The Austrian city of Graz, which has achieved steady growth in cycling, has applied 30 km/h limits to 75% its streets since 1994. [14] Zones where speeds are set at 30 km/h (or 20 mph) are preferred by some [15] as they are found to be effective at reducing crashes and increasing community cohesion. [16] Speed limits which are set below the speed that most motorists perceive to be reasonable for the given road require additional measures to improve compliance. Attempts to improve speed limit observance are usually by either education, enforcement or road engineering. "Education" can mean publicity campaigns or targeted road user training.
Speed limit enforcement techniques include: direct police action, automated systems such as speed cameras or vehicle activated signs or traffic lights triggered by traffic exceeding a preset speed threshold. One cycling expert argues for placing direct restrictions on motor-vehicle speed and acceleration performance. [17] An EU report on promoting walking and cycling specifies as one of its top measures comprehensive camera-based speed control using mainly movable equipment at unexpected spots. [18] The Netherlands has an estimated 1,500 speed/red-light camera installations and has set a target for 30 km/h limits on 70% of urban roads. The UK has more than 6,000 speed cameras, which took more than £100 million in fines in 2006/07. [19]
Traffic calming has been successfully used for decades in cities across Europe. For example, a living street (sometimes known as home zones or by the Dutch word woonerf , as the concept originated in the Netherlands) towards the end of the 1960s, initially in Delft, is a street in which the needs of car drivers are secondary to the needs of other road users; traffic calming principles are integrated into their design. From the Netherlands, the concept spread rapidly to Germany, starting in North Rhine-Westphalia in 1976, and had become very widespread by the early 1980s. The ideas and techniques also spread to the UK towards the end of the 1980s, and practice there was advocated by academics such as Tim Pharaoh and Carmen Hass-Klau. The guidelines published by Devon County Council (of which Tim Pharaoh was the principal author) in 1991 were particularly well received. [20]
In the United Kingdom, Low Traffic Neighbourhoods incorporate traffic calming and filtered permeability. In 2020, some LTNs were introduced with emergency funding from the government, [21] in response to the COVID-19 pandemic. [22] A study found that people living in LTNs in Waltham Forest became less likely to own a car and were more likely to walk or cycle. [23]
School Streets are another UK scheme which involves part-time restrictions on motor vehicles during school pick up and drop off times.
In Ireland, traffic calming schemes have been implemented on national roads since 1993, typically on those with a hard shoulder, on the approach to towns and villages where the speed limit is reduced from 100 km/h to 50 or 60 km/h. This is done by reducing the width of the hard shoulder and the carriageway, various landscaping and installation of 'gateways' in order to reduce the driver's field of view and thus their speed. [24] A gateway marks the transition from high-speed to low-speed road and may feature a pavement, cycle lane, central island (where the road is sufficiently wide enough) or all three, and is accompanied with town/village entrance and speed limit signs as well as bollards and a lamppost in the island.
An evaluation of 91 traffic calming schemes implemented between 1997 and 2002 showed that they were successful in reducing road collisions, the number of which decreased by 13%. The number of fatal collisions was reduced by 52%. [25]
By 2017, San Francisco's Vision Zero program, which heavily features traffic calming, has reduced fatalities by 33%. [26]
A 2018 study found that traffic calming measures in Portland, Oregon reduced excessive speeds, reduced daily traffic volume by 16% and increased home prices by 1%. [27]
The Harrison and 23rd Street Crash Response Project was proposed by the Oakland Department of Transportation (OakDOT) in June 2017 after the death of 68-year-old Oakland resident Robert Bennett (Ferrara 2017).
68-year-old pedestrian Robert Bennett was killed by an unidentified driver turning left from 23rd Street onto Harrison Street (Tolan 2017). The crash was indicative of inadequate safety measures to protect pedestrians at the intersection, especially considering that Harrison Street runs adjacent to Oakland's largest senior center.
In response to the fatality and the subsequent protests by Walk Oakland Bike Oakland, Oakland's Department of Transportation (OakDOT) committed to make Harrison Street more conducive to pedestrians (Tadayon 2017). With a Traffic Engineering Technical Assistance Program grant from the Metropolitan Transportation Commission, the City of Oakland implemented changes that were part of the Vision Zero immediate crash response initiative. Harrison Street was historically a high injury corridor with a concentration of severe traffic-related collisions with "1.8 KSI (kills & serious injuries) per mile" and high speeds with 60% of vehicles over the legal limit (Harrison & 23rd St Crash Response). This problem was exacerbated by the six lanes of traffic on Harrison Street.
In addition to eliminating the left turn from 23rd Street onto Harrison Street, OakDOT's traffic calming scheme notably reduced the number of lanes on Harrison St from six to four. In place of the omitted lanes of traffic, OakDOT elected to add bicycle lanes in each direction and larger median (Harrison & 23rd St Crash Response). The revised median protects pedestrians by giving them more space to stand and added protection from permanent bollards while incorporating curbed ramps to ensure that they can be used by individuals with wheelchairs and strollers. Moreover, bulb-outs were added on each corner of the intersection to slow traffic while protecting pedestrians by reducing the amount of roadway they must cross. The enlarged median and bulb-outs were also painted bright purple making it more visible to drivers with the intention of reducing confusion and effectively making the intersection safer for pedestrians.
Since July 2017, OakDOT added to the original edition of the initiative. The revised edition, supported by the Lakeside Family Streets project and completed in 2019, replaced on street parking on Harrison Street between 20th Street to 27th Street with protected bike lanes. In conjunction with the additional bike lanes, the plan includes protected intersections for cyclists along Harrison Street to omit the need for dangerous mixing zones.
Various forms of traffic calming are used in Japanese cities, particularly in large cities like Tokyo and Yokohama. Tokyo's narrow streets force automobiles and pedestrians to be close to one another; a common traffic calming technique in Tokyo is to change the surface material and/or texture of the shoulder of narrow roads, [28] which helps define the boundary between cars and pedestrians, while allowing cars to use those spaces to pass oncoming traffic.
A Cochrane Review of studies found that there is evidence to demonstrate the efficacy of traffic calming measures in reducing traffic-related injuries and may even reduce deaths. However, the review found that more evidence is needed to demonstrate its efficacy in low income countries. [29]
According to economic commentator and smart growth critic Randal O'Toole, the main goal of traffic calming is to increase traffic congestion for the sake of social engineering. He claims that some traffic calming measures such as reverting one way roads into two-way roads or creating "bump outs" have increased motor traffic congestion, resulted in more crashes and increased pedestrian fatalities. [30] However, Florida urban planner Dom Nozzi argues that "[c]ongestion is a powerful disincentive for sprawl; sprawl that steamrolls outlying ecosystems. With congestion, the sprawl market withers." [31]
Traffic comprises pedestrians, vehicles, ridden or herded animals, trains, and other conveyances that use public ways (roads) for travel and transportation.
Road traffic safety refers to the methods and measures used to prevent road users from being killed or seriously injured. Typical road users include pedestrians, cyclists, motorists, vehicle passengers, and passengers of on-road public transport.
A chicane is a serpentine curve in a road, added by design rather than dictated by geography. Chicanes add extra turns and are used both in motor racing and on roads and streets to slow traffic for safety. For example, one form of chicane is a short, shallow S-shaped turn that requires the driver to turn slightly left and then slightly right to continue on the road, requiring the driver to reduce speed. The word chicane is derived from the French verb chicaner, which means "to create difficulties" or "to dispute pointlessly", "quibble", which is also the root of the English noun chicanery. The Spanish verb chicanear also means "to use trickery".
A curb extension is a traffic calming measure which widens the sidewalk for a short distance. This reduces the crossing distance and allows pedestrians and drivers to see each other when parked vehicles would otherwise block visibility. The practice of banning car parking near intersections is referred to as daylighting the intersection.
Speed bumps are a class of traffic calming devices that use vertical deflection to slow motor-vehicle traffic in order to improve safety conditions. Variations include the speed hump, speed cushion, and speed table.
Rumble strips are a road safety feature to alert inattentive drivers of potential danger, by causing a tactile vibration and audible rumbling transmitted through the wheels into the vehicle interior. A rumble strip is applied along the direction of travel following an edgeline or centerline, to alert drivers when they drift from their lane. Rumble strips may also be installed in a series across the direction of travel, to warn drivers of a stop or slowdown ahead, or of an approaching danger spot.
A living street is a street designed with the interests of pedestrians and cyclists in mind by providing enriching and experiential spaces. Living streets also act as social spaces, allowing children to play and encouraging social interactions on a human scale, safely and legally. Living streets consider all pedestrians granting equal access to elders and those who are disabled. These roads are still available for use by motor vehicles; however, their design aims to reduce both the speed and dominance of motorized transport. The reduction of motor vehicle dominance creates more opportunities for public transportation. Living Streets achieve these strategies by implementing the shared space approach. Reducing demarcations between vehicle traffic and pedestrians create a cohesive space without segregating different modes of transportation. Vehicle parking may also be restricted to designated bays. These street design principles first became popularized in the Netherlands during the 1970s, and the Dutch word woonerf is often used as a synonym for living street.
A road diet is a technique in transportation planning whereby the number of travel lanes and/or effective width of the road is reduced in order to achieve systemic improvements.
Road signs in Norway are regulated by the Norwegian Public Roads Administration, Statens vegvesen in conformity with the 1968 Vienna Convention on Road Signs and Signals, to which Norway is a signatory.
Road traffic collisions generally fall into one of five common types:
Road signs in Thailand are standardized road signs similar to those used in other nations but much of it resembles road signage systems used in South American countries with certain differences, such as using a blue circle instead of a red-bordered white circle to indicate mandatory actions. Until the early 1980s, Thailand closely followed American, European, Australian, and Japanese practices in road sign design, with diamond-shaped warning signs and circular restrictive signs to regulate traffic. The Department of Railway maintains a standard on the typeface used in the sign, with custom made type for Thai text, and a small derivation of FHWA Series fonts typeface, which is used on American road signage, for Latin text.
In the United States, road signs are, for the most part, standardized by federal regulations, most notably in the Manual on Uniform Traffic Control Devices (MUTCD) and its companion volume the Standard Highway Signs (SHS).
Road signs in Israel are regulated by the Ministry of Transportation in the Division of Transportation Planning, most recently set forth in June 2011.
Cycling infrastructure is all infrastructure cyclists are allowed to use. Bikeways include bike paths, bike lanes, cycle tracks, rail trails and, where permitted, sidewalks. Roads used by motorists are also cycling infrastructure, except where cyclists are barred such as many freeways/motorways. It includes amenities such as bike racks for parking, shelters, service centers and specialized traffic signs and signals. The more cycling infrastructure, the more people get about by bicycle.
Road signs in Brunei closely follow the traffic sign regulations used in Singapore as well as the United Kingdom to a lesser extent. A number of changes have also been introduced over the years to suit local road conditions. There are also some differences in the typefaces used, although DIN 1451 remains widely used.
A protected intersection or protected junction, also known as a Dutch-style junction, is a type of at-grade road junction in which cyclists and pedestrians are separated from cars. The primary aim of junction protection is to help pedestrians and cyclists be and feel safer at road junctions.
Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.
Road signs in Lithuania ensure that transport vehicles move safely and orderly, as well as to inform the participants of traffic built-in graphic icons. These icons are governed by the Vienna Convention on Road Traffic and Vienna Convention on Road Signs and Signals.
Road signs in Belgium are defined in the Royal Decree of 1 December 1975 on general regulations for the road traffic police and in the use of public highways. They generally conform to the 1968 Vienna Convention on Road Signs and Signals. The official typeface on road signs in Belgium is SNV.
A stroad is a type of thoroughfare that is a mix between a street and a road. Common in the United States and Canada, stroads are wide arterials that often provide access to strip malls, drive-throughs, and other automobile-oriented businesses. Urban planners have criticized stroads for their safety issues and poor efficiency. While streets provide access to shops and residences at safe traffic speeds, and roads can efficiently move traffic at high speed and volume, stroads pose dangers to drivers and pedestrians and are also prone to congestion.
This section includes a list of references, related reading, or external links, but its sources remain unclear because it lacks inline citations .(September 2020) |
"Department of Transportation's Strategic Plan – January 2019 Update." City of Oakland, January 29, 2019. https://www.oaklandca.gov/resources/department-of-transportation-a- strategic-plan. "Harrison Street/Oakland Avenue Traffic Calming Study Project." Kimley-Horn and Associates, inc, June 18, 2007. "Harrison & 23rd St Crash Response." City of Oakland. Accessed November 2, 2019. https://www.oaklandca.gov/projects/harrison-23rd-st-crash-response. Rudick, Roger. "Eyes on the Street: Lake Merritt BART Intersection Improvements." Streetsblog San Francisco, May 31, 2019. https://sf.streetsblog.org/2019/05/31/eyes-on-the-street-lake-merritt-bart- intersection-improvements/. Rudick, Roger. "Oakland Bollard-Izes Protected Intersections at Lake Merritt." Streetsblog San Francisco, July 1, 2019. https://sf.streetsblog.org/2019/07/01/oakland-bollard-izes-protected- intersections-at-lake-merritt/. Rudick, Roger. "Protected Intersection Update: What's Next?" Streetsblog San Francisco, November 2, 2019. https://sf.streetsblog.org/2019/10/31/protected-intersection-update-whats- next/. Tadayon, Ali. "Quick Fixes Make Oakland Street Where Pedestrian Was Killed Safer; Redesign Underway." East Bay Times. East Bay Times, October 1, 2017. https://www.eastbaytimes.com/2017/09/29/quick-fixes-make-street- where-pedestrian-was-killed-safer-redesign-underway/. Tolan, Casey, and Harry Harris. "Man Killed in Hit-Run near Lake Merritt Ran Social Justice Firm." East Bay Times. East Bay Times, June 5, 2017. https://www.eastbaytimes.com/2017/06/02/oakland-pedestrian-critically- injured-by-hit-run-driver-near-lake-merritt/.
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