For six hours this Sunday, part of West Colfax Avenue will be transformed from a four-lane, car-heavy thoroughfare into a three-lane complete street for people. It’ll be a temporary road diet (built with temporary materials) that demonstrates how simple street design can have an outsize effect on a neighborhood’s safety and sense of place.

Streetsblog Denver covered the demonstration, dubbed “Re-Imagine West Colfax,” last month as the West Colfax Business Improvement District, WalkDenver, and several design firms planned it. Now it’s almost here, and organizers want to get the word out.

The neighborhood’s streets are in dire need of a 21st-century upgrade. Walkscope shows a lack of legitimate sidewalks in the area, and decent crosswalks are even rarer:

But on Sunday the street will go from this:

To something like this:

By calming traffic and creating a safe space for walking and biking, complete streets improve communities. So the event is more than just a demo — it’s a block party for Denverites. Here’s what to expect Sunday, according to the West Colfax BID:

Re-imagine West Colfax is a one-day community celebration and demonstration that will test out creative redesigns that make Colfax more pedestrian and bicycle friendly, including enhanced crosswalks, median refuges, wider sidewalks, small pop-up parks along Colfax, and several types of bike lanes that allow riders to test what it feels like to ride on each. All of these features will be paired with food, music, art and beer. In addition to helping with set-up and tear-down of the event, we need volunteers to host various activity stations throughout the day, including parklets and “Tour de Donut” bike stations. All volunteers will receive a free t-shirt and refreshments!

Demos like Re-imagine West Colfax are some of the best tools advocates have to show Mayor Michael Hancock and other decision makers that complete streets must be funded and implemented — not only to keep people safer but to build better communities. So head down to Colfax and Utica to experience the demo for yourself. The event runs from 10 a.m. to 4 p.m. Organizers needs volunteers, so sign up here if you can help.