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Mr. Fritts. This study shows the difference in the accident rates on those highways that meet modern design and those that do not. The traffic factors are the same. We have the same drivers, the same motor vehicles, the same enforcement, and the same signs and markings.

The chart is of particular interest since it shows the total effect of good standards in reducing accidents as well as variation in accident rates due to traffic volumes mentioned as we will show later.

The 7 bars represent 7 design groups of highways, based on traffic volumes, ranging from 750 in the left over to 22,000 and over on the right.

Senator GORE. Do you have these in tabular form so they can be placed in the record ?

Mr. Fritts. We do not, but we will be able to furnish the committee with a copy of those charts if you so desire.

Senator GORE. That will be fine. As you refer to each one it will be included in the record.

Mr. Fritts. The first 4 bars represent accident rates on 2-lane highways. The fifth covers 2-lane highways in the higher traffic volume groups from 5,000 to 7,700 with partial control access.

The sixth and seventh bars represent the higher traffic range.

You will not that the chart shows at the top the rate on the entire system, including all the highways, good and bad. The gray portion of it shows the accident rate on those highways that have been built today to modern design standards. You will see that the reduction in the rate of accidents varies from 18 percent on the fourth bar, which is the lowest reduction we have, up to as much as 60 percent when modern 4-lane divided controlled access highways are provided.

I would like to call your attention particularly to the 18-percent figure because that shows the effect of large numbers of vehícles on 2-lane highways, 18 and 23 percent, from 3,000 to 7,700 vehicles. It is not possible to make the accident reduction unless additional lanes are provided.

This study shows, overall, that 43 percent of all those accidents might have been prevented if the entire highway system were built to appropriate design standards.

Here is an individual study made in the State of Illinois. This was just completed.

(The chart referred to is as follows:)

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Mr. Fritts. This is a study of 214 miles of highways that have been improved by widening. They are all 2-lane roads. I mention that many of our miles are outmoded in design. There they had the old pavements 18 feet wide. They were rebuilt to 22 feet, which is modern design for highways of that character. We took out of the study, or they took out of the study, those accidents that had nothing to do with the pavement width itself; in other words, intersection accidents, for instance, were taken out of the study.

This refers only to those accidents which occur in moving along, and eliminated the intersection problem. It shows that after widening the rate went down from 230 to start with before the widening to 140 per 100 million vehicle-miles after the improvements were made, or a reduction in the rate of accidents of 39 percent.

Here is another chart which shows the effect of narrow bridges which I am sure you are all aware of. It is one of the bad accident potentials.

(The chart referred to is as follows:)

HOW
WIDTH OF STRUCTURES

AFFECTS ACCIDENTS

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SOURCE : V.S. BUREAU OF PUBLIC ROADS; NATIONAL SAFETY COUNCIL

Mr. Fritts. Where the structure width on the left, for instance, with a narrow guardrail, was narrower than the approach width of the pavement, the accident rate was 100 accidents per hundred million vehicles. Where the bridge was widened and the width was up to 5 feet wider, the rate dropped to 58.

Where the width of the bridge was equal to the width of the roadway it dropped down to 1,200 per hundred million vehicles. That is based on a study in some 10 States on that particular thing.

This is another chart.
(The chart referred to is as follows:)

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SOURCE: DIVISION OF HIGHWAYS, CALIFORNIA

DEPARTMENT OF PUBLIC WORKS Mr. Fritts. Here we show the effect of widening and having adequate shoulders. This is a study made in California involving some 1,169 miles. The accident rate where they had no shoulders at all was 342 per hundred million vehicle miles. İt dropped down to 250 with 2 to 3 feet, and when you got down to 4 to 5 feet, and even 6 to 7 feet, it dropped to 180, and down to 165 when we were over 8 feet wide.

This is another chart.
(The chart referred to is as follows :)

COMPARATIVE ACCIDENTS
SHIRLEY HIGHWAY WITH US. ROUTE 1

20.5

6.1

SHIRLEY
HIGHWAY

DEATH RATE PER 100 MILLION VENICLE MILES

FAIRFAX COUNTY, VA.
JAN. 1,1953 -DEC.31, 1953

Shirley
Wohwgy

U.S. ROUTE 1

wwas

SUMMARY

RT. I
NO ACCIDENTS

27I TOO
INJURY ACCIDENTS

71 34
INJURED

142 67
FATAL ACCIDENTS

10 3
KILLED

10 3
PROPERTY DAMAGE ACCIDENTS 196 63
TOTAL PROPERTY DAMAGE $115,193 $83,428
LENGTH OF SECTION 1320 11,34
ACCIDENT RATE

567 203
(per 100 million vehicle miles)
INJURY RATE

291 128
(per 100 million vehicle miles)
DEATH RATE

20.5 6.1
(per 100 million vehicle miles)
AVERAGE 24-HOUR TRAFFIC 10,134 11,880
SOURCE: VIAGINIA DEPARTMENT OF HIONWAYS

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