Road Safety in Urban Areas

06.12.2020 H. Knoflacher 1

IIT Delhi 2020

Road Safety in Urban Areas

Hermann KnoflacherUniv. Prof. Dipl. Ing. Dr. tech.

Institute for Transport SciencesDivision for Traffic Planning and Traffic Engineering

(Interdisciplinary Mobility and Accessibility Research)Gusshausstrasse 30/231

A-1040 ViennaAustria

+43 1 58801 23122 tel+43 1 58801 23199 fax

http://www.ivv.tuwien.ac.at

Urban Structures


06.12.2020

H.

Kn

ofl

ach

2

0 Evolutionary Preconditions

There are two Optima!

B

walking

running

Pestrian: Negative feedback stabilize the system

Intention/Desire

Sensation

ExperienceNegative Feedback

16.02.01 Prof. H. Knof lacher


Die Zukunft der Motorisierung

Indikator

Pkw/1000EW

1954

Realität 1954 62,4 Pcu/1000 Pop

50 years


10.000 years

Road Safety in Urban Roads



Simulation - Observation

1985


Year 1981

B. Appleyard

What is a slow Speed on Urban Roads?


• 30 km/h

• 40 km/h

• 50 km/h

• 70 km/h


Informationsverarbeitung Schema

ΔT

Δt

Irritation

Stimulus

Action

Reaction


Informationsverarbeitung Schema

Typical time

Spatial limits from

experience


System Speed and Distance!

0

5

10

15

20

25

30

0 5 10 15 20 25 30

Average travel speed [km/h] house - house

Aver

age

travel

len

gth

[k

m]

pedestrian

cyclist

city bus

regional bus

passenger car

neighbourhood relationships


Can you understand the simple message?

A car is approaching from the left with high speed

A a sprahn rmtelf ihhg pe

Aasrh mefih e

Ashmfhe

Speed

4

8

16

32

64

128 km/h

Ahfe

Af


Speed change urban, economic and social structures

Data

Behaviour

STRUCTURESStructures for Cars

Car-DataUrban sprawl and Centralisation

Damage of Public Transport

Car orient. Behav.

Road Design Standards not based on Science


50 m

36 m

24 - 27 m

1964 - 1967

What is the proper lane width ?

Speed and Lane width


Urban Structures?


Sta

nd

ard

La

ne

Wid

th 3

,25 m

30

km

/h

Speed /Ri

sk

? Ethics

? Ethics

Responsibility?

Lane width – car width

Probability to kill people accepted?

Ro

ad

des

ign

Sta

nd

ard

Ro

ad

des

ign

Sta

nd

ard

Helga Kromp-Kolb | BOKU 43

Direction of Responsibility?


The scientific proper lane width

RV – one way traffic

GV – two way traffic

V50% - average speed

Lane Width publ.

1968 - 1985


Chance – equity – for all system users

simultaneous view =

same quality for everybody !

Space for

Pedestrian, Cyclists

and Car users in a

comparable scale

Lane width for

car users (~ T30)

[m]

Satisfa

ction

for x%

50%

85%

06.12.2020 H. Knoflacher49

This are not urban


Motorway and Traffic safety

Is a Motorway a contribution to

Traffic Safety of the System?


Stadtautobahnen

A23 und A22


Effect on Car Traffic

Example:Schlachthausstreet – Motorway A 23

1977 1978 1988

22 000

7.000

26.000 +60.000-

80.000

Forecast, expectation

and modelling by

traditional experts

..the real system effect!

vor 1 year after A23 ...10 years after A23 opening


Expected and observed accidents

Beobachtung und Berechnung stimmen genau

zusammenM L R 1

A b h . V a r i a b l e : U N F

V a r i a b l e n : F U Z O W E R T S C H

B E S C H B E F O V

E W R A D W E G E

B S A B A B S T E L L

G E M S T R P E N D L E R

G E H S T E I G E P K W

1 9 8 3

1 9 8 4

1 9 8 5

1 9 8 6

1 9 8 7

1 9 8 8

1 9 8 9

1 9 9 0

1 9 9 1

1 9 9 2

1 9 9 3

1 9 9 4

1 9 9 5

1 9 9 6

1 9 9 7

1 9 9 8

4 0 0 0

5 0 0 0

6 0 0 0

7 0 0 0

8 0 0 0

9 0 0 0

1 0 0 0 01

97

0

19

72

19

74

19

76

19

78

19

80

19

82

19

84

19

86

19

88

19

90

19

92

19

94

19

96

19

98

S c h ä t z u n g

B e o b

y = x + 1 E - 0 9

R2

= 0 , 9 6 8 7

4 0 0 0

5 0 0 0

6 0 0 0

7 0 0 0

8 0 0 0

9 0 0 0

1 0 0 0 0

4 0 0 0 4 5 0 0 5 0 0 0 5 5 0 0 6 0 0 0 6 5 0 0 7 0 0 0 7 5 0 0 8 0 0 0

S c h ä t z u n g

Be

ob

ach

tu

ng

Nu

mb

er o

f acc

iden

ts w

ith

in

jure

d p

eop

le


.....the formula which produce this effect

Cross – section world view in traditional transport!

A = a x D x S

AccidentsDensity

ru /km

Speed

km / h

x average travel time

= x

but: road users are intelligent, active and selfish

they react on changes – not only in the cross section!

Traditional transport treatment do not see the system

Spec.

Risk of

rux


Solution must take system effects into account

A = a x D x S

Technical progress

Number of Road users

Travel Speed

Interrelationships between this factors can

• progressively enhance accidents

• degressively decrease accidents


Solution today

ΔA = Δa x D x S

Technical progress

Number of Risks

Travel Speed

This interrelationships enhance D and S

Technical effects can/will be compensated

by more car traffic, faster and longer trips


Solution related ot the real system effects:Sustainable Solution

ΔA = Δp x ΔD x ΔS

Technical progress

Number of Risky RU

Travel Speed

Only if the speed of motorvehicles and their

number are reduces substantially we can solve the

accident problem with the contributions from

technical progress


Parking organisation in the right way is the only way

in order to get clean air and safety vor everybody

P P

P P

Pedestrian

only


Big advantage for Citis with Cycle Rikshaws; Clean

air on a bigger scale

P

P P

P

Pedestrian and

Cycle Rikshaws

Clean Air

Safety etc.

No Motorvehicles


Cars have to share public space with the Tram

No additional lanes for private cars anymore


PT-Passengers have Priority


Restoration the Sustainable City


Effect on traffic safety 1991 - 2013

Right size: Arterial Road 17 – 19m wide


Cross section in accordance with

scientific theoretical and practical background


Road Safety in Urban Areas


City Streets are only safe

in Car-free Urban Areas

How we kill Children


Road Safety in Urban Areas

Documents

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