Bobby Sells, AICP Master Plan
- Planning area
- Denver, Colorado
- Edition
- November 2026
Vision
I'm an AICP planner located in Denver, Colorado. My day job is planning and project management on a 650-acre federal campus. In my spare time, I've built Groundrule, which applies the Denver Zoning Code to every lot in the city, and All Aboard Planning, a free study site for planners taking the AICP exam.
LULand Use
Groundrule
Software that applies the Denver Zoning Code to every lot in the city and shows what each one allows.
What it does
A zoning map tells you what a lot is zoned. Groundrule works out what that zoning yields, for all 190,765 lots in its data, and shows each step. I built it on my own time from public city data.
- Site finder
- Ranks the 11,334 lots where today's rules allow at least three more homes than stand there now. Each one opens to a one-page zoning screen.
- Address lookup
- Type any Denver address and get a one-page sheet: what the zoning allows there, how the count is built, and what could change it.
- Lot map
- Shows the homes, floor area, setbacks and constraints for each lot.
- Rule simulator
- Reruns every lot under an amended rule, citywide or for one neighborhood.
- Code checker
- Flags places where two rules point different ways, and rules that need an assumption before they can be applied.
Figure LU-1. Site finder, ranking lots by room for more homes.
Figure LU-2. Address lookup, with the view plane that caps height on this lot.
Select a lot to read its size.
Homes allowed on this block
Figure LU-3. Change the rule, recount the block. A sample block of 22 lots, 125 feet deep, at Denver's common frontages: 25, 37.5, 50 and 62.5 feet. Groundrule runs the same recount on every lot in the city.
Findings
- Denver has 384,794 homes on record. Today's zoning allows about 1.24 million.
- Some lots already hold more homes than today's rules allow. Counting only lots with room left, there is room for about 875,000 more. That is a ceiling under the rules, not a forecast.
- 6% of the city's lots hold 98% of that room.
- Across ten years of permits, 2016 to 2025, multi-unit and mixed-use districts built about 5% of their open room.
- More homes allowed per acre
- under 10
- 10 to 25
- 25 to 50
- 50 to 100
- 100 to 200
- 200 or more
- at the limit
- more homes than rules allow
- not counted
Figure LU-4. Room for more homes under today's zoning, every lot in Denver. Drawn by Groundrule from city parcel data.
384,794 homes on record
About 1.24 million homes allowed by today's zoning
Figure LU-5. Homes on record and homes allowed, to the same scale.
Methods and data
- Every count is a screening estimate, shown with the steps and assumptions behind it. It is not a zoning determination, and anything relied on still gets checked against the adopted code.
- Where a district limits building size but not the number of units, floor area is converted to homes at an assumed average home size.
- Engine tests compare results against values worked out by hand.
- Lot, building and permit data come from the Denver Open Data Catalog (CC BY 3.0). Rules come from the Denver Zoning Code as amended through May 7, 2026.
Groundrule isn't public yet. I'm glad to walk you through it on a call.
Public Realm & Mobility
My day job is planning and project management at the Denver Federal Center, a 650-acre federal campus with three dozen buildings and 5 million square feet of space.
The role
Federal Real Property Specialist with the GSA Public Buildings Service, since May 2021. I also curate the Denver Federal Center Museum: I wrote the campus histories and lead the public tours.
Actions, done and underway
- Daylighted and standardized about three dozen crosswalks.
- Added more than 300 bike parking spaces, and moved many racks from spots that were a hassle to reach to spots that aren't.
- Ran point on EV charger installation, including pilots of several charger types.
- Writing a combined landscape and public realm master plan for the campus. The tree inventory, thousands of trees, is done.
- Evaluating several one-way campus roads for conversion to two-way, for traffic flow and calming.
A car parked against the crosswalk hides the person about to step into it.
Figure PR-1. Daylighting a crosswalk.
CFCommunity Facilities
All Aboard Planning
A free study site for the AICP exam. I built it for the planners taking it after me.
Background
I passed the AICP exam in September 2026 and launched the site a month later. Everything on it is free, including the account.
What's on the site
- 40 lessons
- 9 exam domains
- 5 full-length practice exams
- 850 practice questions
- Flashcards
- Strategy guide
- Quick reference sheet
A property owner sues over a denied rezoning, arguing that zoning itself is unconstitutional. Which U.S. Supreme Court decision first upheld comprehensive zoning as a valid use of the police power?
Pick an answer.
Figure CF-1. Sample practice question.
Neighborhoods
Community and volunteer work, in Denver and abroad.
- Speer & West Washington ParkDenver, Colorado
- Board member of the West Washington Park Neighborhood Association, serving on its zoning committee. The committee's job is to build enough agreement in the neighborhood that a project can move forward.
- Jefferson and Clear Creek CountiesColorado
- At Blue Spruce Habitat for Humanity I started the Home Preservation program, and set up the affiliate's project management and office software.
- North MacedoniaPeace Corps
- Worked in Macedonian with city planners and local officials, and led a mentoring group for high school students.
- OrlandoFlorida
- President of the University of Central Florida's Habitat for Humanity chapter from 2017 to 2019, after joining in 2015. Attended Habitat on the Hill in 2019 on the Emerging Leadership Scholarship.
Existing Conditions
Credentials, education and tools.
| Certification | AICP, 2026. |
|---|---|
| Education | Master of Urban and Regional Planning, University of Colorado Denver Master of Public Administration, University of Colorado Denver B.S. Interdisciplinary Studies, University of Central Florida |
| Current post | Federal Real Property Specialist, GSA Public Buildings Service, Denver Federal Center, since May 2021. |
| Tools | ArcGIS, Power BI, the Adobe suite, Google Apps Script. |
| Languages | Spanish (intermediate), Macedonian (intermediate). |
Implementation
How to reach me.
Email me or send a message on LinkedIn. I'm happy to set up a call and walk through Groundrule.