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Vulnerable Road Users. Hossein Naraghi CE 590 Special Topics Safety June 2003. Time spent: 8 hrs. Pedestrian safety. Pedestrians at risk Research in US indicates Number of pedestrian injuries per head of population is highest for for males 5-9 age group Occurs mostly near victim’s home
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Vulnerable Road Users Hossein Naraghi CE 590 Special Topics Safety June 2003 Time spent:8 hrs
Pedestrian safety • Pedestrians at risk • Research in US indicates • Number of pedestrian injuries per head of population is highest for for males 5-9 age group • Occurs mostly near victim’s home • Victim running across the road • Most occur in the afternoon • Most occur away from pedestrian crossing facility • In many cases the victim did not see the vehicle at all, or saw that too late
Pedestrian safety (continued) • Elderly are the other vulnerable group of pedestrians • Having a lower pedestrian accident rate than most age group • Elderly are more likely to suffer serious injury • In US fatal pedestrian accident rate • exceeds 20 percent for pedestrians over age of 75 years • About 8 percent for pedestrians under age 14 years
Pedestrian safety (continued) • In Britain 50 percent of pedestrian deaths involve people aged over 60 years (Carthy et al 1995) • When crossing a road combination of • Failure of initial judgment • Made by sensory loss with age • Failure to modify behavior to avoid a developing incident • Made by physical and intellectual impairment • Elderly women are more at risk than men taking account for distance walked and roads crossed
Factors contributing to pedestrian accidents • There are some environmental factors which associated with pedestrian accidents • 44% of pedestrian involved in an accident didn’t see the vehicle, 34% of these were saying that they saw the vehicle too late • Due to obstruction caused by parked or stationary vehicles (not involved in the collision) • 8% of pedestrian crashes occur near the bus stop • Pedestrians trying to catch the bus or the pedestrian walking in front of a bus • 20% of pedestrian accident occurred at pedestrian crossing • Due to pedestrian error or driver non-compliance
Factors contributing to pedestrian accidents (continued) • The speed of the vehicle was the contributing factor in 8% of pedestrian accidents • Individual vehicles traveling too fast • A US study indicates that pedestrian accidents • Are mostly occur during morning and afternoon peak periods • Fridays and Saturdays over-represented • Sundays under-represented • 67% of accidents occur away from an intersection • Child pedestrian accident mostly occur at mid-block locations • Adults 45-65 years pedestrian accidents are equally likely to occur at mid-block or intersections • Elderly pedestrian accidents at intersections are more prevalent
Pedestrian safety treatments • Design strategies for pedestrians fall in three categories • Segregation • Spatial separation of pedestrians and vehicular network • Separation • Allocation of either time (pedestrian signals) or space (sidewalks) within a shared pedestrian-vehicle facility • Integration • Through shared use of facility
Pedestrian safety treatments (continued) • Safety effectiveness of pedestrian treatments • Footpaths or sidewalks • Have significant safety benefits where pedestrian volume is high • Residential and business districts • Refuge islands • Permit pedestrians to cross traffic one stream at a time with a safe waiting area at the center of the roadway • Such devices are appropriate when pedestrian crossing movement are concentrated, but overall numbers do not warrant a pedestrian crossing
Pedestrian safety treatments (continued) • Curb extensions • Consists of local widening of the sidewalk into roadway • Reduces the time required by pedestrians to cross the traffic stream • Assist in mutual visibility of pedestrian and motorists • Reduce pedestrian exposure and vehicular delay • Pedestrian barriers • Applicable in locations with high pedestrian activities
Pedestrian safety treatments (continued) • Zegeer and Zegeer (1988) suggest that pedestrian barriers are most beneficial in particular situations • Pedestrian overpasses • Vehicle speeds are high • High volumes of child pedestrians • Little separation between roadway and sidewalk on high speed roads • Near schools and other major pedestrian generators • On bridges with both pedestrian and vehicular traffic
Pedestrian safety treatments (continued) • Traffic signals • Pedestrian facilities at traffic signals may • Have no explicit recognition • Pedestrians have to observe the vehicle signals • Have concurrent phasing • Walk and do not walk display, either in words or symbols • May activate automatically in every cycle • May require pedestrian to use a push button • Have exclusive pedestrian phasing • No potential conflict with vehicular movement
Pedestrian safety treatments (continued) • Based upon an analysis in US, there was no statistical difference between intersections that had walk/don’t walk control and those which had no pedestrian indication • Zegeer 1993 suggests that pedestrian displays are necessary when • Vehicle displays are not visible to pedestrians • Timing is complex • Exclusive turn phases • At school crossing • Exclusive pedestrian-only phase • Allow pedestrian movement in any direction
Pedestrian safety treatments (continued) • Pedestrian crossings • Zebra crossing • Comprised a striped crossing and flashing signals to alert motorist to the presence of crossing • The absence of positive control means that this device is not suitable for • heavy or fast moving traffic (greater than 35 mph) • Pedestrians are constantly using the crossing • Zegeer notes that zebra crossing are “used sparingly in most part of the US because of the uncertainty regarding their potential safety effect”
Pedestrian crossings (continued) • Pedestrian operated signals • Display a red-green-yellow to approaching vehicles, identical to that faced at an intersection • The sequence initiated by pedestrian pressing a button or in some modern facilities, pedestrians are detected automatically • They are more positive than zebra crossing • Pedestrians do not have to expose themselves to risk by stepping onto the crossing • They are suitable for use where signals are linked, heavy or fast moving traffic or heavy pedestrian demands
Pedestrian crossings (continued) • Pelican crossings • A combination of zebra crossing and a pedestrian operated signal • They are used on more heavily trafficked roads • On roads with speed limit of 40 mph or greater, where there are heavy pedestrian flows which would cause delay to motorists • They are used where sight distance is limited
Pedestrian crossings (continued) • Grade separated facilities • Pedestrian overpass and underpass are appropriate • High speed roadway • High traffic flow • Considerable pedestrian delay • High pedestrian accident problem • Restricted access to roadway • A US research indicates that 95% of people will use overpass if there is no loss of travel time
Pedestrian crossings (continued) • Facilities for disabled • Range of provisions that can be provided for people with disabilities such as elderly • Use of tactile surfaces to alert pedestrians • Use of audible tones at signalized pedestrian crossing • Use of ramps at curbs • Attention to the maintenance of surfaces so a smooth, obstruction-free path is available at all times • Raised guide strips at pedestrian crossings to provide assistance to the people with impaired vision • Particular attention to road work and building sites to ensure adequate pedestrian facility remain in place
Pedestrian crossings (continued) • Lighting • To provide a measure of personal security • Enables pedestrians to see hazard or obstacle at night • Appropriate level of lighting should be provided • Higher level of lighting intensity are necessary at • pedestrian crossings • Refuge islands • Outside commercial and retail establishments which trade at night • Pedestrian underpasses
Checklist • Austroads (1995) provided a useful checklist for safety audit of pedestrian schemes which can usefully applied to an examination of current pedestrian facilities • Check the design in three dimension • Ensure that scheme takes account of the likely range of vehicle speed • Ensure that islands are large enough to cater for pedestrians as well as for the necessary street furniture • Ensure pedestrian routes are continuous
Checklist (continued) • Avoid mixing different type of pedestrian controls in close proximity • Minimize pedestrian crossing distances • Where pedestrians are to be deterred from crossing, ensure that fencing is adequate • Provide refuge on heavily trafficked roads to enable pedestrians crossing the road in stages • Ensure pedestrian underpass are wide, straight and open • Ensure pedestrian lighting is adequate • Footpath should be smooth, skid resistance and kept clear from overhanging foliage
Checklist (continued) • Ensure pedestrian walk time are adequate for elderly pedestrians • Provide audio-tactile devices where possible • Ensure that ramps are flush with the invert • Manage parking to maximize sight distance at pedestrian crossing • Ensure that street furniture does not obstruct the vision of pedestrians especially children • Ensure that crossings can be identified and negotiated by visually impaired pedestrians • Ensure that refuge islands are wide enough to accommodate a wheelchair Where possible
Bicyclist safety • Bicyclists are over-represented in fatal crashes • There were 585 fatalities per 10^8 km of travel for bicyclists compare to 112 fatalities per 10^8 km for all road users in Britain • Bicyclists along with other vulnerable road users are significantly under-reported in official road crash statistics • Per capita hour of travel, bicyclists are more than 5 times as likely as car occupants to be killed, while motor cyclists are 30 times as likely to be killed
Bicyclist safety (continued) • Safety strategies • Wearing helmet • Use of brightly colored clothing • Use of under-run barriers on trucks • Education • Legislation such as sanction on • Speeding • Alcohol use • Bicyclist conspicuity • Compulsory wearing of helmet • Provision of bicycle facilities • Explicit consideration of bicyclist needs at intersections
Bicyclist safety (continued) • Bicyclist requirements • There are four basic requirements of bicyclists in relation to the physical facilities they use • A space to ride with adequate lateral clearance • A smooth surface • The ability to maintain speed • Route connectivity and continuity • Bicycle facilities • On-street, mixed traffic bicycling • On-street bicycle only lane • On-street shared bus-bicycle lane • Bicycle use of road shoulders • Bicycle path
Intersection treatments • Problems faced by bicyclists at intersections include • Narrowing of the traffic lane to create a squeeze point • Associated with provision of an extra lane through the intersection for capacity purposes • Insufficient room between the line of vehicles and the curb • Preventing bicyclists from reaching the head of the queue • Bicyclists may have difficulty in moving from the curb lane to the median lane in order to make a left hand turn
Intersection treatments (continued) • In making a left turn, bicyclists are commonly on the outside of the turning traffic, and in potential conflict with opposing left turners • Bicyclists are generally vulnerable at diverge and merge areas for right turners • Signal detectors are not sensitive enough to detect a bicycle unless special detectors are fitted • This may cause insufficient time for bicycle to clear intersection • Bicyclists perceive roundabouts to be unsafe
Intersection treatments (continued) • Attention to the needs of bicyclists in the design of intersections can improve these problems. Some good practices are as follow • Priority controlled intersections • If wide curbside lanes or bicycle lanes are provided, these should be carried through the intersection • Where they can not be carried through, the lane should be terminated well in advance of the intersection (about 170 ft)
Intersection treatments (continued) • Signalized intersections • Curbside approach lanes 13-15 ft wide allow bicyclists to share the lane with motor vehicles • Crossing between roads and bicycle paths • Off-road bicycle path must be accessible with a reasonable length • Bicyclists frequently intersect with roads carrying motor vehicles
Intersection treatments (continued) • The requirements for safe and consistent use of facilities by bicyclists are as follow • Adequate sight distance • Clear indication of termination of the bicycle link • A flat approach, or only a slight gradient • A right angle intersection, or as close to right angle as possible • Effective control of bicycle movements
Attention to detail • Some detail attention in design to provide safe and convenient operating condition include • Ensure that drainage grates cannot trap the wheel of bicycle • Need for lighting for night-time use of facility • Squeeze points or lane drops must be clearly visible to an approaching bicyclist • The need for smooth surface for bicyclists leads to the need for regular maintenance • Adequate sight distance needs to be maintained
Traffic calming • Roundabouts • For single lane roundabouts, an entry lane width of 13-17 ft will provide adequate clearance for bicycles while allowing only single-file vehicle entry • Chicanes • Can create a hazard for bicyclists, since the rider is required to swing out toward the center of the road and share road space with both same and opposing direction
Traffic calming (continued) • Humps • From bicyclists view point, humps • Should not located near the bottom of a steep grade • Should extend across the full width of the road, so that bicyclists are not squeezed • Should have a smooth surface • Road closure • To ensure road connectivity, bicycle access should usually be maintained after street closure