# US 7,607,857 B1 · Assured safe following distance highway markings

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- Number: US 7,607,857 B1
- Document ID: US7607857B1
- Status: Granted
- Kind: B1
- Application number: 11/796,301
- Filed: 2007-04-27
- Granted: 2009-10-27
- Earliest claimed: 2007-04-27
- Inventors: Karl William Swonger, Jr.
- Web page: https://patentgrep.com/patent/US7607857B1

## CPC

- E01F 9/588: Lane delineators for physically separating traffic lanes and discouraging but not preventing crossing
- E01F 9/518: formed in situ, e.g. by painting, by casting into the road surface or by deforming the road surface
- E01F 9/524: Reflecting elements specially adapted for incorporation in or application to road surface markings
- E01F 9/576: Traffic lines
- E01F: ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE

## Abstract

The spacing of road markings is determined as a function of physical and/or environmental road conditions to provide a simple means for vehicle operators to maintain a safe following distance between motor vehicles.

## Claims

### Claim 1

A road marking system comprising a plurality of equally spaced segmented stripes placed upon a surface of a portion of a road with each of said stripes having a length that is directly proportional to a posted speed limit, such that a desired assured safe following distance is maintained for said portion of said road.

### Claim 2 (depends on 1)

The road marking system according to claim 1 wherein said safe following distance is also a function of at least one of a road physical condition and a road environmental condition.

### Claim 3 (depends on 2)

The road marking system according to claim 2 wherein said at least one of said road physical condition and a road environmental condition determines said speed limit for posting.

### Claim 4 (depends on 1)

The road marking system according to claim 1 wherein said segmented stripes are painted parallel to the road direction and further wherein the length of each stripe segment is determined in accordance with the following formula:
L=(S miles/hr.)*5,280 feet/mile*( 1/3,600)hrs./second*T seconds;
where: L is the segment length in feet;
S is the speed limit for the portion of road in miles per hour,
5,280 is a conversion factor to convert miles to feet;
1/3,600 is a conversion factor to convert hours to seconds; and
T is a calibration time period in seconds.

### Claim 5 (depends on 1)

The road marking system according to claim 1 wherein said segmented stripes are painted parallel to the road direction and further wherein the length of each stripe segment is determined in accordance with the following formula:
L=(S km/hr.)*1,000 meters/km*( 1/3,600)hrs./second*T seconds;
where: L is the segment length in meters;
S is the speed limit for the portion of road in kilometers per hour,
1,000 is a conversion factor to convert kilometers to meters;
1/3,600 is a conversion factor to convert hours to seconds; and
T is again a calibration time period in seconds.

### Claim 6 (depends on 4)

The road marking system according to claim 4 wherein said stripe segments are applied to at least one side of said road.

### Claim 7 (depends on 4)

The road marking system according to claim 4 wherein said stripe segments are applied to the center of said road.

### Claim 8 (depends on 4)

The road marking system according to claim 4 wherein said length of each stripe segment changes with changes of said posted speed limit.

### Claim 9

A method for maintaining a safe spacing between a first motor vehicle and a second motor vehicle with the second motor vehicle following the first motor vehicle, the method comprising the steps of:
(a) providing a plurality of equally spaced segmented stripes that are placed upon a surface of a portion of the road and with the stripes being oriented to be parallel to the road and with the length of each of the stripe segments being directly proportional to a posted speed limit for the portion of the road; and
(b) adjusting the speed of the second motor vehicle as needed to maintain the position of the second motor vehicle behind the position of the first motor vehicle by at least the length of one of the stripe segments such that a safe following distance is provided between the first and second vehicles.