Research Trends and Results

Evaluation of the effects of providing side strips onresidential roads
OHASHI Sachiko, Senior Researcher (Dr. Eng.)ONIZUKA Daisuke, Guest Research Engineer
KIMURA Yasushi, Research Engineer
YABU Masayuki, Head
Advanced Road Design and Safety Division, Road Department(Key words) Residential road, providing side strips, traffic safety
1. Introduction
The percentage of traffic accidents which cause
death or injury that are four wheeled vehicle - bicycle
or pedestrian accidents is about 25% on all roads, buthigher at about 32% on residential roads.
And as the figure shows, the fatality rate ofautomobile – pedestrian accidents on residential roads
rises from near the point where the danger perception
speed exceeds 30km/h, and it is believed that
restricting the traveling speed of vehicles to 30km/h orless will prevent serious accidents and reduce traffic
accidents.
Figure. Danger Perception Speed and Fatality Rate
Danger perception speed and death rate of pedestrians on
residential roads※(Accidents from 2008 to 2012)
60.0%

Fatality rate (%)

50.0%

Fatalityrate

40.0%

Number of fatal
accidents53.9%
47.9%

Total number ofaccidents causing
death or injury

32.0%
30.0%

cost than hard methods, to verify its effectiveness.

2. Analysis of the effectiveness of providing sidestrips
This research surveyed the state of travel on roads
with similar roadside conditions etc. and analyzed thetraveling speeds of vehicles, clarifying its
effectiveness.
The analysis assessed the significance of differences
between vehicle speeds on multiple similar routes
where only one road structure element differs. The
table shows the results.
Table. Significance of Speed Differences by Road
Structure Element
Overall assessment ofsignificance*
Analysis items (road structure elements)
Average Maximum
speedspeed
Center line Center line placed/not placed○○
Traffic
Traffic restriction△△
restrictions enforced/not enforced

17.5%

20.0%

Road width (two-way traffic)○○

Road width (one-way traffic)△△

Roadside strip provided/notprovided△△

Width of roadside strip○

×

Vehicle lanes Width of vehicle lanes△
×△Both sides colored/notcolored△△Comparison of one side andboth sides

××

Differences in color

××

Road width
6.2%

10.0%

0.5%

0.9%

Fatality rate (%)

1.6%

0.0%
Less than Less than Less than Less than Less than Less than Less than
10km/h
20km/h
30km/h
40km/h
50km/h
60km/h
70km/h

70km/hoverSide strip

Danger perception speed [km/h]*Here residential roads are municipal roads
Prepared by the NILIM based on ITARDA data

One side colored/not colored

Color

There are two traffic safety countermeasuremethods: hard methods such as installing humps,
chicanes, or narrowingss and other structures torestrict speed, and soft methods such as restricting
traffic. The effectiveness of implementing many hardmeasures has been confirmed by past research, but theeffectiveness of taking soft measures has not beenverified as often as that of hard measures.
This research has focused on providing side strips,
which is a soft method that gains local approval
relatively easily, and which can be installed at lower△*Case where significance of 5% is considered significant○：Significant difference between all streets analyzed△：Partial significant differences between all streets analyzed
×：No significant differences between all streets analyzed

Significant differences in speed were confirmed
between roads with and without a center line andaccording to road widths (two-way streets), and it canbe stated that these impact the reduction of travelingspeed. There were partial significant differences
according to traffic restrictions, road width (one-waystreet), side strip width, and road width. And regardingcoloring, which is counted on mainly to clarify side
strips or regulate traffic, excluding one part, nosignificant differences in speed were confirmed.
3. Future directions
The comparison of routes did not clarify theeffectiveness, although it did show a tendency for thespeed to differ according to differences in road
constituent elements. So now states of travel before
and after countermeasure on the same route are being
compared. And to clarify the effectiveness ofmeasures other than speed restrictions, a questionnaire
survey will be carried out to confirm the feelings ofsafety of users.
In the future, we want to organize these effects foreach condition such as road width to clarify the mosteffective way to construct side strips.