Interpass: Uninterrupted, Grade-Level Interchange having One-way Approach and Departure Legs

Abstract

The Interpass: Uninterrupted, Grade-Level Interchange having One-way Approach and Departure Legs is a geometric design for an at-grade interchange of one-way roadways that has no conflict points and which allows uninterrupted, uniform-velocity traffic flow. The subject invention is neither an overpass, nor an underpass, nor an at-grade intersection, nor a grade-separated interchange, and it has comparatively few of the negative qualities associated with those types of roadway junctions. Uninterrupted, grade-level interchanges of the subject design, when connected into a directed transportation network having one-way roadway segments, can constitute the nodes of an intrinsically-safe, grade-level, arterial or collector transportation facility with superior controllability, efficiency and safety, compared to those of traditional facilities.

Claims

1. A geometric design, as described in the specification and drawings heretofore attached, for a roadway junction that: a. is entirely grade-level, b. has no conflict points, allowing uninterrupted, uniform-velocity traffic flow, c. may have any integer number, greater than or equal to two, of inbound, one-way approach legs, each approach leg having any positive-integer number of lanes, and d. provides at least two unique choices of outbound direction, via one-way departure legs, for each inbound approach leg.

2. In reference to claim 1 of this section, each permutation of every combination of numbers of approach legs and numbers of approach leg lanes of the subject invention comprises a different embodiment of the invention.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0105] A plan view of a geometric design for a Double Interpass (uninterrupted, grade-level interchange with two inbound one-way approach legs), with each approach leg having two lanes, is shown in FIG. 1 on Sheet 1/5 of the drawings. The approach legs, on the west and east sides of the figure (with north represented as toward the top of the sheet) each split (bifurcate) as they approach the junction point (in the direction of traffic flow), with one lane turning to the right and the other to the left. Those lanes then continue to turn away from the junction point and depart away from the junction without having crossed, or otherwise intersected, any other lane or roadway. Adjacent departing lanes (not separated by an intervening approach leg) join together to form one-way departure legs, illustrated in FIG. 1 as extending to the north and to the south of the junction point. The arrows represent one-way inbound and outbound roadway segments which would attach to the one-way approach and departure legs, respectively, of the interchange and which would connect the interchange to other interchanges to form a roadway network. The arrows also indicate the direction of traffic flow and whether traffic is approaching (inbound to) or departing (outbound from) the junction.

[0106] FIG. 2 on Sheet 2/5 is a plan view depicting another embodiment of the invention: a Double Interpass (uninterrupted, grade-level interchange with two inbound one-way approach legs) with each of the approach legs having four lanes.

[0107] FIG. 3 on Sheet 3/5 is a plan view depicting yet another embodiment of the design, as an example, showing a Triple Interpass (uninterrupted, grade-level interchange with three inbound one-way approach legs) with each approach leg having two lanes.

[0108] FIG. 4 on Sheet 4/5 is a plan view depicting a grade-level transportation network having Double Interpasses (uninterrupted, grade-level interchanges, each with two inbound one-way approach legs) as the nodes of the network. The nodes (interchanges) would be connected by one-way roadway segments, represented by arrows showing the direction of traffic flow.

[0109] FIG. 5 on Sheet 5/5 is a plan view depicting a grade-level transportation network having Triple Interpasses (uninterrupted, grade-level interchanges, each with three inbound one-way approach legs) as the nodes of the network. The nodes (interchanges) would be connected by one-way roadway segments, represented by arrows showing the direction of traffic flow.

DETAILED DESCRIPTION OF THE INVENTION

[0110] The Interpass is a geometric design for a roadway junction that is entirely at-grade (nominally confined to a horizontal plane) and has any number, N, of one-way approach legs, such that N is an integer greater than or equal to two. The number of one-way approach legs classifies the junction as an “N-tuple”. For example, an Interpass junction having two approach legs is a “Double Interpass Junction”; one having three approach legs is a “Triple Interpass Junction”; one having four approach legs is a “Quadruple Interpass Junction”, and so forth, with each N-tuple interpass junction being a different embodiment of the subject invention.

[0111] Each approach leg may have any positive-integer number of lanes. The lanes of the approach legs—and of all roadways within the junction—must be hard lanes in order to prevent abrupt lane changes within the junction that could create conflict points or require abrupt directional changes or driver reactions.

[0112] The set of different embodiments of the invention includes all possible permutations of all possible combinations of numbers of approach legs and numbers of lanes composing each of the approach legs.

[0113] Described directionally from the viewpoint of flowing traffic, each approach leg bifurcates (splits) as it approaches the junction, with one or more lanes turning to the right, and one or more lanes turning to the left. The split can occur along a boundary between lanes, or could occur in the center of a lane such that the split lane becomes two lanes—one diverging left, and one diverging right. The boundary-split is preferred to the center-lane split, as the latter could, under certain circumstances, form a diverging conflict. If an inbound segment/approach leg has only a single lane, then its bifurcation must be a center-lane split. After each approach leg bifurcates, the lanes turning to the right continue to turn away from the junction point and become departure leg lanes, without crossing or merging with any other lane, as do those turning to the left. Adjacent departing lanes (those not separated by an intervening approach leg) are joined, without merging, as they depart the junction, to form a single, one-way departure leg. The total number of departure legs of the interchange should then equal the number of approach legs. The lanes of departure legs that join together must remain as hard lanes, with no two lanes converging into a single lane, for that could create a merging conflict.

[0114] Within the Interpass junction, all the roadways are one-way, all of the lanes are hard lanes, and no lane or roadway crosses or intersects with any other. As such, there are no conflict points, and traffic through the interchange can flow uninterrupted at uniform velocity. Also, because each approach leg has two departure legs from which a departure direction from the junction may be chosen, the Interpass is a well-connected interchange (minimum density 2).