Gas station and c-store site fit calculator

How the calculator reads a gas station

The calculator starts from two numbers a fuel site program fixes early: the vehicle fueling positions (VFP), each place where one vehicle can fuel at a time, and the floor area of the convenience store. ITE's 11th Edition bands land use 945, Convenience Store/Gas Station, by store size and fueling position count, and its PM peak rates rise from 18.42 to 26.90 trips per VFP as the store grows ^[1]. From those two inputs the calculator estimates the PM peak hour trips, compares them with the traffic study triggers of the state and the place, and lists the turn-lane warrants, the state's underground storage tank (UST) program agency, the dispenser separations, the parking rows and the dimensions of the delivery design vehicle you choose. Each figure it shows is read from a row cited to its source. The gas station site plan page shows how those distances shape the layout around the pumps, the store and the canopy.

Trips from fueling positions and store size

The City of Phoenix, Oregon, republishes the 11th Edition PM peak rates for land use 945 in three bands: 18.42 per VFP for a store of 2,000 to 4,000 sf with 8 or fewer VFP, 22.76 for 4,000 to 5,500 sf with 12 to 20 VFP, and 26.90 for 5,500 to 10,000 sf with about 16 VFP ^[1]. The calculator picks the band by the store size you enter, multiplies its rate by your fueling positions, and labels the result with the edition and the table it comes from ^[1]. A store of exactly 4,000 or 5,500 sf sits on a limit two bands share as the table writes them, so the calculator shows both estimates and does not choose between them ^[1]. The fueling position count a band names is shown beside the estimate and never used to pick the band, and a store under 2,000 or over 10,000 sf gets no estimate, because no band in the table covers it ^[1].

Florida holds the exception in the rows. Palm Beach County requires the FDOT two-variable equation instead of ITE, and prohibits internalization between pumps and store ^[2]. The county's table gives 12.3 x VFP + 15.5 x (store ksf) PM peak trips, split 50/50, a daily volume of 14.3 x PM trips, and "Use PM" for the AM peak, from an FDOT study the county adopted on 7/25/2022 ^[2]. Where you choose Palm Beach County, the calculator computes that equation, compares its PM peak figure with the triggers, and shows the ITE band beside it. The Florida site plan page covers the decision clocks and state layers a Florida application meets.

Pass-by changes what a traffic study counts. Phoenix, Oregon applies net-new factors of 0.44, 0.25 and 0.21 by size band ^[1]. The calculator states those factors with their label and never applies them, because the table, as our research reads it, does not pair each factor with a band. ITE's own pass-by shares for land use 945 are not verified in our research, and neither are its daily and AM peak rates per fueling position.

Traffic studies and turn lanes

Each state's transportation department sets traffic study thresholds for access to its highways, and some cities and counties set their own; the calculator shows the rows of the state you choose and of the place, where our research holds one. Arizona's TGP 240 calls for a traffic impact analysis at 100 or more trips in any one hour, Category I from 100 to under 500 and Category II at 500 or more, and a traffic statement under 100 ^[3]. Ohio calls for a full TIS above 200 peak-hour trips, a Traffic Analysis at 60 to 200, and a turn-lane warrant submission only at 10 to 59 ^[4]. Virginia's administrative guidelines set study tiers of 100 to 499 and 500 or more peak-hour trips ^[5], and 24VAC30-155-40 calls for a rezoning submission at more than 5,000 vehicle trips per day at a state highway connection ^[6]. Texas has no single statewide trip threshold ^[7], and the TxDOT Houston District calls for a major study at 150 or more peak-hour or 1,500 or more daily trips ^[8]. The Texas gas station site plan page covers TxDOT access on frontage roads and state highways.

The calculator compares its PM peak estimate only with a trigger that counts trips in a peak hour or in any one hour, and the county equation's daily figure only with a daily trigger. A trigger that counts new trips is stated and not compared, because the estimate comes before any pass-by reduction. North Carolina's threshold of 3,000 or more daily trips allows no trip reductions when testing it, and below it the District Engineer decides ^[9].

Turn-lane warrants count turning vehicles at a driveway, which the calculator does not estimate, so it shows them as the rows state them. Georgia sets right-turn lanes by daily site right-turn volume: on a 2-lane road with AADT under 6,000, 200 at 35 mph or less, 150 at 40 to 50 mph and 100 at 55 to 60 mph, and always at 65 mph or more ^[10]. Colorado's access code sets a deceleration lane at more than 25 vph of right-turn ingress in access category R-A ^[11]. Arizona's TGP 245 warrants a left-turn lane at 30 vph under 45 mph, or 15 at 45 mph or more, when advancing volume is under 200 ^[12]. The Georgia gas station site plan page covers the access geometry GDOT fixes on the plan, and the Gwinnett County gas station and c-store case study is a model project on the county's rulebook.

Tanks, dispensers and separations

Underground storage tanks answer to a state agency where EPA has approved the state's program. Under 40 CFR Part 282, an approved program operates in lieu of the federal one, and as of September 2021, 39 states plus the District of Columbia and the Commonwealth of Puerto Rico had approved programs ^[13]. The calculator names the agency of each state where our research verified it: the TCEQ PST Program under 30 TAC Ch. 334 in Texas ^[14], the EPD UST Management Program under Ga. Comp. R. and Regs. 391-3-15 in Georgia ^[15], and the TDEC Division of USTs under Tenn. Comp. R. and Regs. 0400-18-01 in Tennessee ^[16]. For every other state it says the agency is not verified in our research.

The siting distances start from the model codes. The International Fire Code puts dispensers 10 ft or more from lot lines (IFC 2303.1 item 1; NFPA 30A 6.2.1), 10 ft or more from buildings with combustible walls or non-rated noncombustible walls, and 20 ft or more from fixed ignition sources (IFC 2303.1 items 2 and 5), and it places the emergency shutoff within 100 ft of, but not less than 20 ft from, dispensers (IFC 2303.2) ^{[17, 18]}. Those distances bind only where a state or city has adopted them, so the calculator labels them a model standard. Virginia's code, 13VAC5-52-280, sets dispensing at least 10 ft from adjoining buildable lot lines and 5 ft from building openings, prohibits smoking and open flames within 20 ft of dispensers, and puts dispensers within 10 ft of vehicle traffic on a 6 in concrete island or Section 312 protection ^[17]. New Hampshire applies NFPA 30A as adopted in its 2021 edition: the emergency shutoff not less than 20 ft nor more than 100 ft from dispensers, and 75 ft maximum travel to an extinguisher ^[19].

Local rules sit on top of the model codes, and the calculator shows a county or city row only where it was verified from the code. Prince George's County, Maryland, allows a gas station by special exception under Zoning Sec. 27-358(a), with the nearest pump 300 ft from any lot with a school, outdoor playground, library, hospital or residence, and 150 ft of frontage on a 70 ft right-of-way ^[20]. Phoenix's Zoning Ordinance §623 keeps tractor-trailer stacking and loading docks at least 60 ft from residential zoning ^[21]. The car wash and gas station regulations by state guide sets these rules beside each state's tank program and fire code.

Parking and the delivery truck

Parking codes rarely name a gas station with a convenience store as a use of its own, so the calculator shows a city's rows by the code's own condition. Houston's Sec. 26-492 Class 9(e) sets 3.0 spaces per service stall plus 1.0 per employee on the largest shift for a service station, and the convenience store component is not verified in our research ^[22]. Tulsa's Table 55-1 sets 1.50 per 1,000 sq ft for a fueling station and 2.50 per 1,000 sq ft for convenience goods retail, with none for the first 5,000 sq ft, under Ord. 25429, effective 12/10/2024 ^[23]. How Tulsa's two ratios combine is not verified in our research. Milwaukee sets parking for a filling station as required by the board for special use approval ^[24]. The parking requirements lookup holds the same rows beside other uses and asks the location questions where a city's no-minimum area or a state parking law applies.

The delivery truck sets the turning path at the driveways and around the canopy, but which design vehicle a fuel delivery uses is not verified in our research, so the calculator shows the dimensions of the vehicle you choose and never picks one. TxDOT's Roadway Design Manual Table 4-1 gives the WB-67 interstate semi-trailer a 44.8 ft minimum design turning radius, a 41.0 ft centerline turning radius and a 1.9 ft minimum inside radius ^[25]. INDOT's Figure 40-4A, the archived 2006 English edition, lists the same vehicle as WB-65, the Indiana Design Vehicle, with an overall length of 73.5 ft, a width of 8.5 ft and a height of 13.5 ft, and gives the SU-30 single-unit truck a length of 30.0 ft ^[26]. Sites that also fuel tractor-trailers are covered on the truck stop site plan page, and the car wash stacking calculator covers a wash bay added to a fuel site.