self regulating streets

March 2013

SELF-REGULATING STREETS

Jason TaylorUrban Designer - South Dublin Co Co .

Self-Regulating Streets

• The Issue of Speed

• Speed and Street Characteristics

• A Balanced Approach

Speed is a key issue in street design

– Impact on safety

– Impact on enjoyment, vitality, use by more sustainable/active modes

• Road Safety Authority Free Speed Survey 2008, 2009, 2011

– Consistent findings, on average 3 out of 5 drivers on urban roads driving in excess of the posted speed limit.

– On Primary/Secondary routes, 2 out of 5 drivers were driving 10km/h or more over the posted speed limit

The Issue of Speed

• There is a long established relationship between speed and street design

• Transport Research Laboratory (UK) reports 322, 325 and 551

– Driver speed based on a visual and psychological interpretation of street environment

– Legislation and regulation play a secondary role

The Issue of Speed

• Self-regulating streets instinctively tell drivers what speed they should be doing (i.e. visual and psychological interpretation)

• Self regulating streets are established by a combination of 'soft' and 'hard' measures.

• Softer 'place' based measures include

– Built form

– Landscape

– Activity

• Harder measures are more associated with conventional road design, i.e. street geometry

Speed and Street Characteristics

• Physical and psychological, or harder and softer measures, that influence driver behaviour illustrated in the Adamstown Street Design Guide (2010).

• No single measure is effective on it own. Physical and psychological measures are most effective when used in combination (Transport Research Laboratory 2005).


• Preparation of DMURS included an analysis of recent Road Safety Authority Free Speed Surveys to establish influence of 'hard' and 'soft' measures on drivers in Ireland

• RSA Free Speed Survey 2008, 2009 and 2011 recorded speeds of some 9,500 vehicles in free flowing conditions along 23 streets, that varied in function and context, within metropolitan Dublin were recorded

Stillorgan Road (N11) Navan Road (N3) Morehampton Road (N11) Clonkeen Road (R827)

Lwr. Kilmacud Road (R825) Delwood RoadAbbey Park Glasilawn Road


• The results demonstrated a strong trend whereby as the frequency and strength of the 'softer', or psychological, and 'harder', or physical, design measures increased, operating speeds lowered significantly

Average Operating Speed (All Streets)

Frequency and Intensity of Psychological and Physical Measures

Stillorgan Road (60 km/h)

Ave. 71.6 km/h

Lwr Kilmacud Rd (50 km/h)

Ave. 48.7 km/h

Brian Rd (50 km/h)

Ave. 31.0 km/h



• and the number of drivers exceeding the posted speed limit significantly decreased

% of Drivers Exceeding the Posted Speed Limit (All Streets)


Stillorgan Road (60 km/h)

83.6%

Lwr Kilmacud Rd (50 km/h)

37.6%

Brian Rd (50km/h)

1%

• As would be generally expected the presence of deflections (such as ramps) had a strong influence on reducing speed. However trend of lower operating speeds was consistent on streets without ramps where other measures were present.

Average Operating Speed (Streets Without Ramps)


Morehampton Rd (50 km/h)

Ave. 53.3 km/h

Delwood Road (50 km/h)

Ave. 44.8 km/h

Lorcan Rd (50 km/h)

Ave. 34.7 km/h


• Other ‘softer’ measures, such as a sense of enclosure, surveillance and activity created by landscape treatments and development (esp. where fronting directly onto the street) also had a significant influence on lowering speed.

Average Operating Speed (Enclosure and Frontage)


Malahide Road (60 km/h)

Ave. 69.8 km/h

Brookwood Rise (50 km/h)

Ave. 38.3 km/h


Morehampton Rd (50 km/h)

Ave. 53.3 km/h

• Significantly, where there are limited psychological and physical design measures on streets with a speed limit of 50 km/h, most drivers exceeded the speed limit by 10 km/h or more.

% of Drivers Exceeding the Speed Limit by 10km/h or more (50 km/h streets)



• Research highlights the need to re- evaluate much of what has been accepted as convention

• DMURS highlights issues with conventional design approaches that seek to minimise risk and delay for motor vehicles

• This approach is counter productive in urban areas as drivers are more inclined to drive at inappropriate speeds and behave more aggressively

• Further implications for sustainability and quality of life. If streets are not perceived to be safe, people will retreat to the safety of their cars

A Balanced Approach

• To moderate speeds, streets need to be fronted with development and overlooked with only as much space dedicated to motor vehicles as is reasonably necessary

• DMURS equips designers with the tools to create more equitable distribution of risk and responsibility

• DMURS presents designers with a holistic package 'soft' and 'hard' measures to manage driver behaviour and increases pedestrian/cyclist mobility

• 'win win' - more attractive, better managed streets promote the development of more sustainable communities

A Balanced Approach

50 km/hMid Level Place Function

Mid Level Movement Function

30 km/hMid Level Place Function

Low level Movement Function

10 km/hHigh Level Place Function

Low level Movement Function (Cars)

High Level Movement Function

(Pedestrians/Cyclists)

A Balanced Approach

50 km/hMid/High Level Place

Function


30 km/hHigh Level Place

Function


>30 km/hHigh Level Place Function

Mid Level Movement Function (Cars)


(Pedestrians and Cyclists)

A Balanced Approach

• Legislation and enforcement alone will not adequately manage vehicle speeds.

• Research also tells us that conventional design measures alone do not sufficiently manage driver speeds

• Driver speed is best managed by a combination of 'hard' and 'soft' measures

• Place based design promotes a 'win win' scenario, where streets are more attractive, more sustainable and safer.

Conclusion

self regulating streets

Design

issue of speed speed

driver speed

posted speed limit

psychological measures

physical measures

streets stillorgan road

design measures

street geometry