---
title: "Displaced Left-Turn (DLT) retrofit"
url: "https://commonwaysystem.org/retrofits/intersection/displaced-left-turn-dlt-retrofit/"
id: "RFT-INT-04"
description: "Shifts the left-turn lane to the opposing side of oncoming traffic upstream of the main intersection, letting left-turning and opposing through traffic move simultaneously without a dedicated protected phase."
updated: "2026-10-18"
---

RFT-INT-04

# Displaced Left-Turn (DLT) retrofit

Shifts the left-turn lane to the opposing side of oncoming traffic upstream of the main intersection, letting left-turning and opposing through traffic move simultaneously without a dedicated protected phase.

## Strategy viewer

Illustration in progress

No illustration of Displaced Left-Turn (DLT) retrofit has been made yet. Interactive views are planned for every pattern and Retrofit Strategy.

## Overview

Also known as a continuous flow intersection, this retrofit resolves the same unprotected-left-turn conflict that Median U-Turn and RCUT address, but through signalized displacement rather than a median crossover. A driver turning left crosses opposing traffic at a signal well before the main intersection, then proceeds through the main intersection on a green phase running concurrently with through traffic in both directions, since the crossing conflict has already been resolved upstream.

## Related Media

The items below come from outside the Commonway System, external videos, podcasts, and articles related to this page's topic, not part of the guidebook itself.

Aligned

### [The Intersection That Makes Left Turns Impossible](https://www.youtube.com/watch?v=3nLK9GzfqHA)

Safe By Design

This video explains how the Restricted Crossing U-Turn removes left turns and crossing movements from the side street, with crash-reduction results from Alabama, Nebraska and North Carolina and an honest look at the longer pedestrian crossings it can create. It is a close companion to the Commonway System's RCUT pattern and retrofit strategy, and to the related Median U-Turn and Displaced Left-Turn designs.

MED-089

## Where this leads: Target patterns

-   [Displaced Left-Turn (DLT)](https://commonwaysystem.org/patterns/intersections/displaced-left-turn.md) (INT-DLT-14)

## Applicability and thresholds

Requires substantial additional right-of-way width upstream of the main intersection to build the displaced left-turn crossing, which is this retrofit's primary limitation compared to Median U-Turn or RCUT.[2] Most viable at high-volume urban or suburban intersections where a grade-separated interchange isn't justified but conventional signal delay from protected left-turn phasing is severe.

## Evidence and effectiveness

DLT is documented as a faster, lower-cost alternative to a grade-separated interchange at high-volume intersections, resolving left-turn and through-movement conflicts without the cost of a flyover or underpass, though at higher construction cost and impact than Median U-Turn or RCUT.[1]

## Getting it built

Cannot be piloted informally. Widening for the displaced left-turn crossing is real, costly construction, frequently impacting adjoining properties given the additional area required. This strategy effectively starts at Permanent on the construction spectrum. See [Construction Methodology & The Build Spectrum](https://commonwaysystem.org/guide/construction-methodology-spectrum.md).

An Intersection Control Evaluation is standard practice, and given the higher cost and impact of this design relative to Median U-Turn or RCUT, is particularly important for justifying the additional expense. See [Decision & Evaluation Processes](https://commonwaysystem.org/guide/decision-evaluation-processes.md).

## Who can move this

Typically a state DOT or large-city capital project, given the cost and right-of-way scope involved. See [Legal & Planning Mechanisms](https://commonwaysystem.org/guide/legal-planning-mechanisms.md) and [Funding & Financing Mechanisms](https://commonwaysystem.org/guide/funding-financing-mechanisms.md).

## Related retrofit strategies

-   [Median U-Turn (MUT) retrofit](https://commonwaysystem.org/retrofits/intersection/median-u-turn-mut-retrofit.md) (RFT-INT-02)
-   [Restricted Crossing U-Turn (RCUT) retrofit](https://commonwaysystem.org/retrofits/intersection/restricted-crossing-u-turn-rcut-retrofit.md) (RFT-INT-03) (the two lower-cost alternatives addressing the same underlying unprotected-left-turn problem)

## References

1.  Evidence-based ["Unconventional Arterial Intersection Designs under Connected and Automated Vehicle Environment: A Survey," on Displaced Left-turn Intersection design and cost tradeoffs relative to grade-separated interchanges.](https://arxiv.org/abs/1811.03074)
2.  Legal / regulatory [U.S. Patent 7,135,989, "Parallel flow vehicle turn system for traffic intersections," on displaced left-turn retrofit considerations and right-of-way impacts.](https://patents.google.com/patent/US7135989B2/en)