US 5,795,095 A · Simultaneous left turn vehicular intersection

Abstract

A right hand traffic intersection at grade of four roadways and method of directing vehicles to cross an intersection center bidirectionally along two opposed roadways in Phase 1, along the other two roadways in Phase 2, and to make simultaneous protected left- or U-turns from all four roadways, with through-traffic stopped, in Phase 3 of a 3-phase signal cycle. Two left turn passages in each roadway located between incoming and outgoing main lanes terminate at the intersection center at two locations, cross at an interchange zone some distance from the center and connect to the main lanes yet farther from the center. Vehicles making a left turn enter the center from the left passage whereas traffic arriving from a left turn enter the right passage. This keeps all left turn tracks in the center apart. Traffic signals control traffic at the intersection center and interchange zones. The design and methodology for a three-roadway, "T"-shaped, intersection is similar. The stem of the "T" has two left turn passages and an interchange zone, the right top has a single left turn lane and the left top has none. Signals follow a 2-phase cycle, during Phase 1 vehicles may cross the intersection center bidirectionally in the top of the "T", and in Phase 2 vehicles may make simultaneous protected left- or U-turns from the stem and from the right top with through-traffic stopped.

Claims20

Dependent claims

An intersection for right-hand vehicular traffic accommodating four intersecting roadways at grade, having an intersection center, and in each roadway comprising:

a) Incoming and outgoing main lanes for flow of incoming and outgoing traffic relative to said center, said lanes meeting said center at two locations;
b) A left turn lane complex positioned between said main lanes consisting of oppositely directed passages for flow of incoming and outgoing left turn traffic relative to said center, said passages crossing at an interchange zone some distance removed from said center, said zone dividing the incoming passage into a turnout lane and a left turn lane, and dividing the outgoing passage into a receiving lane and a merging lane, said left turn lane and receiving lane joining said center at a first and second left turn junction respectively, said first junction being to the left of said second junction viewed by a driver approaching said center, and the remote ends of said turnout and merging lanes joining said incoming and outgoing main lanes respectively;
c) A track through said center connecting said incoming main lane in one roadway with said outgoing main lane in the roadway opposite;
d) A track through said center connecting said first left turn junction with a corresponding second left turn junction of the roadway to the left;
e) Traffic control means at said interchange zone;
and
f) Traffic signal means located where said incoming main lane meets said center and at said first left turn junction timed so as to permit traffic to flow along said main lanes in the first pair of opposed roadways in a first phase, along said main lanes in the opposed pair in the cross direction in a second phase, and to make simultaneous protected left turns from, and optionally U-turns in all four roadways, with said main lane flow stopped, in a third phase of a three-phase signal cycle, which then repeats itself.

4 more elements

An intersection for right-hand vehicular traffic accommodating three intersecting roadways at grade configured approximately in the form of a "T" and having an intersection center and

a) Each roadway having incoming and outgoing main lanes for incoming and outgoing traffic relative to said center, said lanes meeting said center at two locations;
b) In the stem of the "T" having a left turn lane complex positioned between said main lanes consisting of oppositely directed passages for incoming and outgoing left turn traffic relative to said center, said passages crossing at an interchange zone some distance removed from said center, said zone dividing said incoming passage into a turnout lane and a left turn lane, and dividing said outgoing passage into a receiving lane and a merging lane, with left turn lane and receiving lane joining said center at a first and second left turn junction respectively, said first junction being to the left of said second junction as viewed by a driver approaching said center, and the remote ends of said turnout and merging lanes joining said incoming and outgoing main lanes respectively;
c) A track through said center connecting said incoming main lane in either of the two opposed roadways forming the top of the "T" with said outgoing main lane of the roadway opposite;
d) A track through said center connecting said first left turn junction of said stem with said outgoing main lane of said left half of said top;
e) A track through said center connecting a left turn lane of said right half of said top to said second left turn junction of said stem;
f) Traffic control means at said interchange zone in said stem;
and
g) Traffic signal means located where said incoming main lanes meet said center in said two roadways of said top and at the junction of said incoming left turn lanes in said right top and in said stem, timed so as to permit traffic to flow along said main lanes in said pair of opposed roadways in said top in a first phase, and to make simultaneous protected left turns from, and optionally U-turns in said right top and said stem with said main lane flow stopped, in a second phase of a two-phase signal cycle, which then repeats itself.

5 more elements

Dependencies are inferred from the claim text.

Simultaneous left turn vehicular intersection

Life of this patent

Simultaneous left turn vehicular intersection

Life of this patent

Abstract

Claims20