Weaving free two level cloverleaf type interchange for a highway crossing under a street

Abstract

The weaving free two level cloverleaf type local interchange for a highway crossing under a street accommodates traffic from a plurality of traveled ways which include a first traveled way for traffic traveling in a first direction, a second traveled way for traffic traveling in a direction opposite to the first direction, a third traveled way for traffic traveling in a direction intersecting the first and second traveled ways, and a fourth traveled way for traffic traveling in a direction opposite to the traffic traveling on the third traveled way. The first and second traveled ways cross under the third and fourth traveled ways. Each of the first and second traveled ways has a design speed compatible to a highway or freeway design speed, or is designed according to highway or freeway design standards. Each of the third and fourth traveled ways has a design speed compatible to the design speed of a street, road, or a conventional highway, or is designed according to the design standards of a street, road, or a conventional highway. In the preferred embodiment, the first traveled way left turn ramp crosses under the third and fourth traveled ways, then crosses over the first and second traveled ways, and finally joins the fourth traveled way. The second traveled way left turn ramp crosses under the third and fourth traveled ways, then crosses over the first and second traveled ways, and finally joins the third traveled way. In the additional embodiment, the third traveled way left turn ramp crosses over the first and second traveled ways, then crosses under the third and fourth traveled ways, and finally joins the first traveled way. The fourth traveled way left turn ramp crosses over the first and second traveled ways, then crosses under the third and fourth traveled ways, and finally joins the second traveled way. The present invention eliminated the highway and street weaving sections. Each fly over or under ramp has a better horizontal curve and achieves minimum number of slope, sag and crest, which represents a better geometric design than the one in the interchange in U.S. Pat. No. 4,861,184. The present invention has higher efficiency and safety standard than a conventional cloverleaf type local interchange and the interchange in U.S. Pat. No. 4,861,184. The two level configuration, compact ramp geometric design, higher safety, and better efficiency make this interchange a better choice for congested urban highway system.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS[0001]Not applicable.FEDERALLY SPONSORED RESEARCH[0002]Not applicable.SEQUENCE LISTING OR PROGRAM[0003]Not applicable.BACKGROUND OF INVENTION[0004]1. Field of Invention[0005]This invention relates to cloverleaf type local interchanges, specifically, to weaving free two level cloverleaf type local interchanges.[0006]2. Prior Art[0007]The conventional cloverleaf type local interchange was patented on Feb. 29, 1916 under U.S. Pat. No. 1,173,505. It has the following disadvantages:[0008](a) This type of local interchange has highway weaving sections for fast moving vehicles swapping lanes at grade. A safe and efficient highway weaving section requires a long weaving length and thus large Right of Way. However, most local interchanges can not have such large Right of Way for the required weaving length. Traffic moves slowly inside the highway weaving sections. The Level of Service in the highway weaving sections is usually F during peak hours in ur...

AI Technical Summary

Problems solved by technology

However, most local interchanges can not have such large Right of Way for the required weaving length.

The efficiency of this interchange is low.

(b) The highway weaving section is a source of traffic congestion on the highway because the queue stretching from the highway weaving section to the highway blocks highway traffic.

(c) The street weaving section is a source of traffic congestion on a busy street because the street weaving blocks street traffic.

(d) Traffic accidents occur inside the highway weaving sections because of the competition between the highway bound traffic and street bound traffic in the highway weaving section.

Some of these can be fatal.

The cloverleaf type local interchange has safety problems.

(e) The queues stretching from the highway weaving section to the highway also cause traffic accidents on the highway.

(f) Traffic accidents happen in busy street due to the street weaving.

Therefore, the conventional cloverleaf type local interchange has low efficiency, causes traffic congestion, and bears safety problems.

(a) This invention fails to achieve a substantially straight line horizontal alignment in the high speed zone of any flying over or under ramp. The ramp that flies over or under the highway has a left turning curve, a short straight segment, and a right turning curve in the high speed zone. The ramp that flies over or under the street has a left turning curve in the high speed zone.

(b) This invention fails to use minimal number of horizontal curve in any fly over or under ramps. Each fly over or under ramp has three horizontal curves. Two of them turn to the opposite directions. Because of these curves, the ramp would be made very long in order to meet stop sight distance requirements, which could render this type of interchange infeasible for local interchanges due to availability of right of way. Or, safety and efficiency could be compromised.

(c) This invention fails to achieve a flat profile in the high speed zone of any flying over or under ramp. The profile of the ramp flying over the highway goes up and down, and then reaches the highway elevation again before it crosses under the street. The profile of the ramp flying under the highway descends and ascends, and then reaches the highway elevation again before it crosses under the street. Drainage for the ramp flying under the highway would be a big issue. The profile of the ramp flying over or under the street is a slope instead of a flat profile in the high speed zone.

(d) This invention fails to utilize minimal number of slopes for any flying over or under ramps. All the flying over or under ramps have three slopes.

(e) This invention fails to use minimal number of sags and crests in the profile of any flying over or under ramp. The ramp profile has a combination of either three sags and two crests, or two sags and three crests. These sags and crests make the ramp very long in order to meet the stop sight distance requirements, which could render this type of interchange infeasible for local interchanges due to availability of right of way. Or, safety and efficiency will be compromised.

(f) This invention is a three level interchange in the cases of a ramp flying under the highway or over the street. This three level configuration for a local interchange does not blend well with urban environment.

Therefore, there are deficiencies in safety and efficiency.

This patent may not be feasible for local interchanges.

The three level configurations do not fit urban environment well.

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