Walkable streets, smaller lots

The ASMP's wider streets are meant for things most people want: wider sidewalks, street trees, bike lanes and better transit. The land for them comes from the lots along those streets, and the cost doesn't stop at the strip itself. In Austin, allowed floor area and impervious cover are calculated from lot size. When land is dedicated, it leaves the site, and those allowances shrink with it. Setbacks also move back with the new lot line. That trade-off is real on both sides. The useful question is how big the cost is, where it lands, and which policy choices make it smaller.

The rule we applied

For every lot, we compared each adjacent street's required right-of-way in the ASMP Street Network Table with the street's width today, measured lot line to lot line from city parcel data. Each side of the street gives up half the gap, measured from its existing lot line. That follows the Land Development Code's alignment rule (§25-6-54) and the Transportation Criteria Manual's half-width standard (Table 10-6). Some examples of how far apart the published widths and today's streets are: Required widths from the ASMP Street Network Table (City of Austin GIS, edited Oct 11, 2026; also viewable on the city's Street Network Map). Today's widths are measured lot line to lot line; ranges show the 10th to 90th percentile along each stretch.

The published width is a starting point

The full-width numbers in this post are the city's opening position, not a forecast of what any project will dedicate. What a project ends up giving is set case by case:

• Many projects never trigger it. Dedication is tied to rezoning, platting and site plans. Building one to four units on an existing lot only needs a building permit, which doesn't trigger it.
• It's capped. The city can only require an amount roughly proportionate to the project's traffic impact (LDC §25-6-23).
• It can be reduced or replaced. Variances (§25-6-86), public access easements in place of a dedication (TCM §2.7.3), and administrative relief on Level 1 streets for small infill projects all lower the take.

To show that range, we ran four versions of the same rule: Share of private parcel land inside the dedication strip. "Likely" counts only lots zoned for multifamily or commercial, whose redevelopment would trigger dedication.
One note on the often-quoted estimate of 5–6%: it matches measuring the full width from the city's mapped street centerline (5.9% in Brentwood). That mapped line sits more than 5 ft off the middle of the actual street in about 45% of the places we checked, so we measured from real lot lines instead, which gives 4.2%.

Explore Austin's Right of Way Rules

Pick a neighborhood, then click any lot. The panel shows the rule applied to that lot (each street's level, required width, today's width, and the feet taken from that side) and draws the lot five ways: today, with the full published width, with half the gap, and with full width plus two different setback rules.

BrentwoodNorth LamarHancock

MapSatellite

Find a lot

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Share of lot in the full-width stripnone<3%3–10%10–25%>25%

Brentwood · 2,569 lots · 824.6 acres of private land

Full ASMP widths would take 4.2% of Brentwood's private land

In strips

1.52M sf

Avg per lot

592 sf

Lots touched

2,321

Median touched lot

3.5%

Likely: lots that trigger dedication2.1%

Half the gap2.1%

Full published width4.2%

From mapped centerline5.9%

Most of the strip land sits on N Lamar Blvd, W Koenig Ln, Burnet Rd. Click any lot to see the rule applied to it.

What it means for a project

• Most lots lose a thin strip. The median lot touched in Brentwood gives up 3.5% of its area, usually along a local street.
• Arterial frontage carries the load. About 44% of Brentwood's strip land sits on Level 3–4 streets like N Lamar and Koenig, where the median strip is about 13 ft deep. 221 Brentwood lots would lose more than 10% of their land.
• Setback rules matter as much as the strip. Across Brentwood, full dedication cuts buildable area by about 5%. Measuring setbacks from the future curb instead of the new lot line brings that loss under 1%.
• Easements protect entitlements. When the wider sidewalk sits in a public access easement instead of a dedication, the land stays part of the site, so allowed floor area and impervious cover don't drop.

Austin is already looking at some of this. A resolution on the May 28, 2026 Council agenda (item 26-1851) asks staff to review street setbacks in commercial, office and multifamily zones and to tie site standards to right-of-way designation. Numbers like these can help size what's at stake.

How we built this and what it leaves out

We used city GIS layers for the ASMP street network, TCAD parcels, zoning and 2023 building footprints, and applied the code's setback, FAR and impervious cover rules lot by lot. It's a scenario analysis, not a prediction of actual dedications or housing loss. A few things it doesn't capture yet:

• Corner clips and extra right-of-way at intersections
• Core Transit Corridor sidewalk easements and build-to lines on N Lamar
• Rules specific to PUDs, conditional overlays and other special districts, which we modeled with base-district setbacks
• Buildings built or demolished since 2023

Existing buildings that sit in a strip stay legal. They're only affected if the lot redevelops, so we don't count them as homes lost. If you're weighing a site where this matters, we'd like to hear what you're seeing in review. And if you'd like this run for a neighborhood or corridor you're working in, let us know.