Mestrado Integrado em Engenharia Civil Mestrado em Engenharia … · Pedestrians Mestrado Integrado em Engenharia Civil Mestrado em Engenharia do Território Disciplina: Engenharia

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Mestrado Integrado em Engenharia Civil

Mestrado em Engenharia do Território

Disciplina: Engenharia de Tráfego Rodoviário

Prof. Responsável: Filipe Moura

Session 11: Pedestrians

(Source: HCM 2000)

Engenharia de Tráfego Rodoviário / Road Traffic Engineering MEC (Urbanismo, Transportes e Sistemas), MET, MPOT, MUOT 1

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Analysis of pedestrian flows and LOS

•  The analysis of pedestrian flow generally is based on the mean walking speeds of groups of pedestrians.

•  Within and among groups there can be considerable differences in flow characteristics due to trip purpose, type of group, age, and other factors.

•  The LOS criteria for pedestrian flow are based on subjective measures, which can be imprecise.

•  It is possible to define ranges of space per pedestrian, flow rates, and speeds, which then can be used to develop quality-of-flow criteria.

•  Speed is an important LOS criterion because it can be observed and measured easily, and because it is a descriptor of the service pedestrians perceive.


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Concepts and definitions (I)

•  Speed (average pedestrian walking speed) usually in m/s. •  Pedestrian flow rate - the number of pedestrians passing a point per unit of time,

expressed as pedestrians per 15 min or pedestrians per minute –  Pedestrian flow per unit of width is expressed as pedestrians per minute per meter (p/min/

m).

•  Pedestrian density is expressed as pedestrians per square meter (p/m2).

•  Pedestrian space is the average area provided for each pedestrian in a walkway or queuing area. It is the inverse of density, and is often a more practical unit for analyzing pedestrian facilities.

•  Platoon refers to a number of pedestrians walking together in a group, usually involuntarily, as a result of signal control and other factors.


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Concepts and definitions (II)

•  The qualitative measures of pedestrian flow are similar to those used for vehicular flow, e.g. freedom to choose desired speeds and to bypass others.

•  Measures related specifically to pedestrian flow include: –  ability to cross a pedestrian traffic stream –  walk in the reverse direction –  to maneuver without conflicts and changes in walking speed, and –  the delay experienced by pedestrians at signalized and unsignalized intersections.

•  Additional environmental factors that contribute to perceived LOS are –  Comfort, convenience, safety, security, and economy of the walkway system.

•  Comfort –  Weather protection, climate control, transit shelters, and other pedestrian amenities.

•  Convenience –  Walking distances, pathway directness, grades, sidewalk ramps, directional signing,

directory maps, etc.


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Concepts and definitions (III)

•  Safety –  Physical or time separation (traffic control devices) of pedestrians from vehicular traffic on

the same horizontal plane

•  Security –  Lighting, open lines of sight, and the degree and type of street activity

•  Economic aspects are related to costs due to –  Delays and inconvenience –  Commercial values and retail development influenced by pedestrian accessibility

•  These supplemental factors can affect pedestrian perceptions of the overall quality of the street environment, from which the pedestrian has virtually no control over them, and are not analyzed quantitatively.


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Level of Service in walkways (I)


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Level of Service (II)


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Level of Service in waiting areas or queues (I) •  In waiting areas, the pedestrian stands temporarily, waiting to be serve and LOS is related to the

average space available to each pedestrian and the degree of mobility allowed. •  In queuing areas, LOS is based on average pedestrian space, personal comfort, and degrees of

internal mobility •  LOS E ,at 0.2 to 0.3 m2/p, are encountered only in the most crowded elevators or transit vehicles. •  LOS D, at 0.3 to 0.6 m2/p, describes crowding, but with some internal maneuverability.


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Level of Service in waiting areas or queues (II)


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Relations between speed and density, flow and space, and flow and speed

•  The conditions at maximum flow represent the capacity of the walkway facility.

•  Maximum unit flow fall within a narrow range of density, ]0.4,0.9[ m2/p.

•  Even the outer range of these observations indicates that maximum flow occurs at this density, although the actual flow in this study is considerably higher than in the others.

•  As space is reduced to less than 0.4 m2/p, the flow rate declines precipitously.

•  Note: all movement effectively stops at the minimum space allocation of 0.2 to 0.3 m2/p.


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Relations between speed and flow and between space and speed (I)

where Vped = unit flow rate (p/min/m) Sped = pedestrian speed (m/min) Dped = pedestrian density (p/m2) M = pedestrian space (m2/p)

!

Vped = Sped "Dped

!

Vped =Sped

M

These relationships suggest that pedestrian traffic can be evaluated qualitatively by using LOS concepts similar to vehicular traffic analysis.


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Space occupied by pedestrians


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Space occupied by pedestrians


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Analysis period and input requirements

•  The duration of an analysis period for pedestrians is typically 15 min. It is difficult to predict flow patterns like platoons based on a longer analysis period.

•  A midblock walkway should be counted for several different 15-min time periods during the day to establish variations in directional flows.


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Default values


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Walking speed

Average walking speed •  Depends on the proportion of elderly pedestrians (65 years walking speed of age

and older) in the walking population . –  % of elderly pedestrians is between 0% to 20% , the value of of 1.2 m/s is recommended. –  % of elderly pedestrians is above 20% , the value of of 1.0 m/s is recommended

•  An upgrade of 10 percent or greater reduces walking speed by 0.1 m/s.


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Effective Walkway Width (I)

•  The concept of a pedestrian lane should not be used for pedestrian analysis, because studies have shown that pedestrians do not walk in organized lanes.

•  Walkway is meaningful for determining how many persons can walk side by side –  To avoid interference when two pedestrians pass each other, each should have at least 0.8m

of walkway width –  The Portuguese legislation (DL 163/2006) - states that width in each sidewalk should be at

least 1.5 meters. •  Effective walkway is the portion of a walkway that can be used effectively for pedestrian

movements –  Moving pedestrians shy away from the curb and do not press closely against building walls –  Similarly, stripes are preempted by pedestrians standing near a building, or near physical

obstructions, such as light poles, mail boxes, and parking meters –  These unused spaces must be discounted when analyzing a pedestrian facility –  A single point of obstruction would not reduce the effective width of an entire walkway, it

would have an effect on its immediate vicinity


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Effective Walkway width (II)

where: •  WE = effective walkway width (m), •  WT = total walkway width (m), •  Wo = sum of widths and shy distances from obstructions on the walkway (m).


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Preemption of walkway width (I)


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Preemption of walkway width (II)


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Uninterrupted-flow pedestrian facilities

•  Uninterrupted pedestrian facilities include both exclusive and shared pedestrian paths designated for pedestrian use.

–  Pedestrians do not experience any disruption except the interaction with other pedestrians. •  Variables used: pedestrian space requirements, walking speed and pedestrian start-up time.

–  Space: It can be directly observed in the field by measuring the sample area of the facility and determining the maximum number of pedestrians at a given time in that area.

–  Speed: It can be observed readily in the field, and can be used as a supplementary criterion to analyze a walkway or sidewalk.

•  Pedestrian unit flow rate is used as a service measure –  Determination of the peak 15-min count and the effective walkway width is required to compute pedestrian

unit flow rate.


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Pedestrian unit flow rate

where: •  vp = pedestrian unit flow rate (p/min/m), •  v15 = peak 15-min flow rate (p/15-min), •  WE = effective walkway width (m).

•  Volume to capacity (v/c) ratio can be computed assuming 75 p/min/m for capacity.


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Platoons

•  Platoon formation is due to short-term fluctuations resulting from random arrivals of pedestrians

•  On sidewalks, these random fluctuations are exaggerated by the interruption of flow and queue formation caused by traffic signals

•  Transit facilities can create added surges in demand

•  Until they disperse, pedestrians in these types of groups move together as a platoon

•  Platoons also can form if passing is impeded because of insufficient space

•  LOS in platoons is generally one level lower than the average flow criteria for LOS

RELATIONSHIP BETWEEN PLATOON FLOW AND AVERAGE FLOW


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Effect of Platoons on Walkways and Sidewalks

•  If platooning arises the following LOS table should be used. •  Even though LOS table represent platooning and other patterns of flow, the analyst enters the

tables with average unit flow rate. •  The previous equations apply to all flow patterns.


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LOS in Stairs

The modified LOS criteria for stairs are to ensure that the basic equation of traffic flow is satisfied. The volume to capacity (v/c) ratios are based on a stairway capacity of 49 p/min/m.


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Conflict in crossing pedestrians

•  A cross flow is a pedestrian flow that is approximately perpendicular to and crosses another pedestrian stream.

•  In general, the smaller of the two flows is referred to as the cross-flow condition. –  A pedestrian’s streams ability to cross a pedestrian stream is unimpaired if M > 3.5 m2/p –  If M <1.3 m2/p => every crossing movement encounters a conflict


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Uninterrupted-flow pedestrian facilities Cross Flows

•  For pedestrian streams of roughly equal flow in each direction, there is little reduction in the capacity of the walkway compared with one-way flow, because the directional streams tend to separate and occupy a proportional share of the walkway.

•  If the directional split is 90% versus 10%, and space is 1.0 m2/p, capacity reductions of about 15% have been observed. The minor flow is unable to use a proportionate share of the walkway.

•  The same procedure for estimating walkway and sidewalk space is used to analyze pedestrian facilities with cross flows. Accordingly, LOS criteria A through D are to be used. Only for LOS E the values are different:


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Queuing Areas

•  The average space available to pedestrians also can apply as the walkway service measure for queuing or waiting areas.

•  The LOS thresholds are related to the average space available to each pedestrian and to the degree of mobility allowed.

•  In dense standing crowds, there is little room to move, but limited circulation is possible as the average space/pedestrian increases.


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Signalized Intersections •  The signalized intersection crossing is more complicated to analyze, since it involves

intersecting sidewalk flows, pedestrians crossing the street, and others queued waiting for the signal to change.

•  Research indicates that the average delay of pedestrians at signalized intersection crossings is not constrained by capacity, even when pedestrian flow rates reach 5,000 p/h

•  The service measure is the average delay experienced by a pedestrian given by: where: •  dp = average pedestrian delay (s), •  g = effective green time (for pedestrians) (s), and •  C = cycle length (s).


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Pedestrian Area Requirements at Street Corners

•  There are two types of pedestrian area requirements at street corners. –  A circulation area is needed to accommodate pedestrians crossing during the green

signal phase, those moving to join the red-phase queue, and those moving between the adjoining sidewalks but not crossing the street.

–  A hold area is needed to accommodate pedestrians waiting during the red signal phase. •  The methodology can identify problem locations that may require detailed field

study and possible remedial measures - widening the sidewalk, adding restrictions on vehicle turns, and changing the signal timing.

•  The analysis of street corners and crosswalks compares available time and space with pedestrian demand.

•  The product of time and space (or time-space) is the critical parameter, because physical design limits available space, and signalized controls limit available time.


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Intersection corner geometry and pedestrian movements


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Condition 1 – Minor Street Crossing

•  Condition 1 - minor-street crossing phase during the major street green, with pedestrians queuing on the major-street side during the minor-street red phase.


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Condition 2 – Major Street Crossing

•  Condition 2 - major-street crossing phase, with pedestrians crossing during the minor-street green, and queuing on the minor-street side during the major-street red phase.


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Available Time-Space Street Corner Time-Space

•  Total time-space available for circulation and queuing in the intersection corner during an

analysis period is the product of the net corner area and the length of the analysis period. •  For street corners, the analysis period is one signal cycle and therefore is equal to the cycle

length.

where •  TS = available time-space (m2-s), •  Wa = effective width of Sidewalk a (m), •  Wb = effective width of Sidewalk b (m), •  R = radius of corner curb (m), •  C = cycle length (s).


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Holding-Area Waiting Times Condition 1

•  Assuming arrivals are uniform at the crossing queue, the average pedestrian holding times can be computed for Conditions 1 and 2.

•  These equations reflect the proportion of the cycle time that flows are held up, as well as their holding time based on the red signal phase.

•  For Condition 1 the holding-area waiting time is given by :

where: •  Qtdo = total time spent by pedestrians waiting to cross the major street during one cycle (p-s) •  vdo = the number of pedestrians waiting to cross the major street during one cycle •  Rmi = the minor-street red phase, or the Don't Walk phase if there are pedestrian signals (s) •  C = cycle length (s)


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Holding-Area Waiting Times Condition 2

where: •  Qtco = total time spent by pedestrians waiting to cross the minor street during •  one cycle (p-s); •  vco = the number of pedestrians waiting to cross the minor street during one cycle

•  Rmj = the major-street red phase, or the Don't Walk phase if there are pedestrian signals (s); •  C = cycle length (s).


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Determining Circulation Time-Space

•  Net corner time-space available for circulating pedestrians is the total available time-space minus the time-space occupied by the pedestrians waiting to cross.

•  The holding area required for waiting pedestrians is the product of the total waiting time and the area used by waiting pedestrians.

Where: •  TSc = total time-space available for circulating pedestrians (m2-s), •  TS = total time-space available (m2-s), •  Qtdo = total time spent by pedestrians waiting to cross the major street during one cycle (p-s), •  Qtco = total time spent by pedestrians waiting to cross the minor street during one cycle (p-s).


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Pedestrian Space

•  The space required for circulating pedestrians is computed by dividing the total time-space available for circulating pedestrians by the time that pedestrians consume walking through the corner area (sum of the total circulation volume multiplied by 4 s, the assumed average circulation time).This yields the area for each pedestrian, which is related to the LOS thresholds for walkways (uninterrupted flow)

where: •  M = circulation area per pedestrian (m2/p); •  TSc = total time-space available for circulating pedestrians (m2-s); •  vtot = total number of circulating pedestrians in one cycle = vci + vco + vdi +vdo + va,b


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Crosswalk Time-Space

where: •  TS = time-space (m2-s); •  L = crosswalk length (m); •  WE = effective crosswalk width (m); •  WALK + FDW (flashing don’t walk) = effective pedestrian green time on crosswalk (s); •  Sp = average speed of pedestrians (m/s); •  G = green time for phase, if WALK + FDW is not installed (s).

The analysis of crosswalk time-space requires a pedestrian flow rate during the cycle length interval..


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where: •  t = total crossing time (s), •  L = crosswalk length (m), •  Sp = average speed of pedestrians (m/s), •  Nped = number of pedestrians crossing during an interval (p), •  W = crosswalk width (m), •  3.2 = pedestrian start-up time (s).

where: •  Nped = number of pedestrians crossing during an interval (p); •  v = pedestrian volume on the subject walkway (p/15-min); •  G = green time for phase, if WALK + FDW is not installed.


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•  The total crosswalk occupancy time is computed as a product of the average crossing time and the number of pedestrians using the crosswalk during one signal cycle.

where: •  T = total crosswalk occupancy time (p-s), •  vi = inbound pedestrian volume for the subject crosswalk (p/cycle), •  vo = outbound pedestrian volume for the subject crosswalk (p/cycle), •  t = total crossing time (s).


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•  The circulation space provided for each pedestrian is determined by dividing the time-space available for crossing by the total occupancy time.

•  This yields the area provided for each pedestrian, which is related to LOS thresholds for walkways (uninterrupted flow)

where: •  M = circulation area per pedestrian (m2/p), •  TS = time-space (m2-s), •  T = total crosswalk occupancy time (p-s).


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•  The time-space method allows for an approximate estimate of the effect of turning vehicles on the LOS for pedestrians crossing during a given green phase. This assumes an area occupancy of a vehicle in the crosswalk, based on the product of vehicle swept path, crosswalk width, and estimate of the time that the vehicle preempts this space.

•  The swept-path for most vehicles is 2.4 m, and it can be assumed that a vehicle occupies the crosswalk for 5 s.

where •  TStv = time-space occupied by turning vehicles (m2-s), •  Ntv = number of vehicles during the green phase (veh), •  WE = effective width of crosswalk (m).

•  This value is subtracted to the crosswalk time space


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Mestrado Integrado em Engenharia Civil Mestrado em Engenharia … · Pedestrians Mestrado Integrado em Engenharia Civil Mestrado em Engenharia do Território Disciplina: Engenharia