Quick Summary:
- Locate the four letter SIPP code on your voucher or quote.
- Use the first letter to gauge size, comfort, and boot space.
- Check letters two and three for doors, body style, and transmission.
- Confirm the fourth letter for fuel type and air conditioning included.
SIPP codes are a four letter shorthand used across car hire to describe a vehicle category in a consistent way. In California, you will often see a SIPP code on your rental voucher, supplier confirmation, or comparison results. The code does not promise an exact make and model, but it does tell you the class and core features the supplier should provide, subject to availability. Once you know how each letter works, you can spot common mismatches, such as expecting an automatic but choosing a manual class, or assuming a larger boot than the class typically allows.
This matters in California because driving styles and journeys vary. City driving around San Francisco can favour a smaller footprint, while family road trips from Los Angeles to national parks often need luggage space and comfortable seating. When you compare car hire options, SIPP decoding helps you choose the right class before you pay, and it helps you check your voucher matches what you intended.
What a SIPP code looks like
A standard SIPP code has four letters, such as CDAR or IFAR. Each letter has a job, and reading left to right gives you a structured description.
Letter 1: vehicle category and approximate size or segment.
Letter 2: body style and number of doors, sometimes seating layout.
Letter 3: transmission and drivetrain.
Letter 4: fuel type and whether air conditioning is included.
Not every supplier uses every possibility in every location, but the structure remains consistent enough to be useful. If your voucher shows only a category name like “Intermediate SUV”, ask the supplier or check the listing details for the SIPP, because it is a faster way to validate the essentials.
Letter 1, decoding the size category
The first letter is your quickest signal for how much space and comfort to expect. Different brands sometimes label segments slightly differently, but SIPP categories commonly map like this.
M: Mini, very small city cars, limited boot.
N: Mini Elite, small but upgraded trim.
E: Economy, small and efficient, common for short trips.
H: Economy Elite, similar size with upgraded spec.
C: Compact, a step up in cabin and boot space.
D: Compact Elite, compact size with higher trim.
I: Intermediate, comfortable for longer drives and luggage.
J: Intermediate Elite, similar size with added features.
S: Standard, often larger saloons or roomy crossovers.
F: Fullsize, more shoulder room and boot capacity.
P: Premium, higher spec, sometimes larger engines.
L: Luxury, top tier comfort and features.
X: Special, can mean unique classes, not strictly size based.
In California, “Intermediate” and “Standard” are common sweet spots for mixed city and highway driving. If you are picking up at a major hub such as Los Angeles Airport (LAX), you may see a wider spread of first letters because inventory is larger.
Letter 2, decoding doors and body style
The second letter can be the most confusing because it compresses body style, door count, and sometimes seating format. Here are common values you might see on a California car hire voucher.
B: 2 door, small body style.
C: 2 or 4 door, often used for compact hatchbacks.
D: 4 door, typical saloon or sedan setup.
W: Estate or wagon, longer boot, practical luggage space.
V: Passenger van, people carrier or minibus style.
L: Limousine style, premium saloon category in some systems.
S: Sport, performance oriented body style.
T: Convertible, open top.
F: SUV, higher ride height.
J: Open air all terrain, less common.
Door expectations are important for families, mobility needs, and car seats. A two door class may be cheaper, but it can be awkward for rear access. If you are travelling with more people and luggage, you may prefer a van class, and it is helpful to compare a dedicated people carrier option such as minivan rental at San Francisco (SFO) rather than assuming an SUV will solve space.
Letter 3, decoding transmission and drivetrain
The third letter is where many travellers avoid costly surprises. In the US, automatics are common, but manuals still appear in some categories, and hybrids and electric vehicles can introduce different drivetrain labels. Typical third letters include.
M: Manual transmission.
A: Automatic transmission.
N: Manual with four wheel drive, less common.
B: Automatic with four wheel drive.
C: Manual with all wheel drive, rare in some fleets.
D: Automatic with all wheel drive.
If you are not used to US driving, choosing an automatic can reduce stress, especially in stop start traffic on California freeways or steep streets in San Francisco. Also note that four wheel drive or all wheel drive is not automatically included just because the car is an SUV. The SIPP third letter is your best clue. When comparing options for car rental at San Francisco Airport, look at that third letter if you plan to drive to mountain areas where traction can matter in winter conditions.
Letter 4, decoding fuel and air conditioning
The fourth letter usually covers fuel type and whether the vehicle has air conditioning. In California, air conditioning is the norm, but the code still helps you confirm it. Common fourth letters include.
R: Unspecified fuel with air conditioning.
N: Unspecified fuel without air conditioning.
D: Diesel with air conditioning.
Q: Diesel without air conditioning.
H: Hybrid with air conditioning.
I: Hybrid without air conditioning.
E: Electric with air conditioning.
C: Electric without air conditioning.
For most California trips, you will want an “R” or a fuel specific letter that still includes air conditioning. If your code ends in “N” or another no air conditioning marker, double check the listing, because it is uncommon and could indicate an older or special fleet category.
Putting it together, reading common SIPP examples
Once you know each position, you can decode quickly. For example, CDAR typically means Compact, 4 door, Automatic, air conditioning. IFAR usually means Intermediate, SUV, Automatic, air conditioning. These interpretations are most reliable for the transmission and air conditioning letters, which is why decoding is so useful for avoiding a mismatch with your driving preferences.
If you are collecting from a smaller airport, inventory may be tighter, which can make class substitutions more likely. In those cases, having a clear grasp of the class code helps you evaluate whether an offered alternative is genuinely equivalent. If you are browsing options around Orange County, car hire at Santa Ana Airport (SNA) listings can include a range of compact, intermediate, and SUV classes, so decoding the code is a quick way to keep your comparison consistent.
How SIPP helps you choose the right car hire class in California
Use SIPP decoding as a checklist before you commit to a class.
1) Match the transmission to your comfort. If you need automatic, the third letter should be “A”, “B”, or “D”.
2) Check doors and access needs. If you will be loading child seats or frequent luggage, favour four door and consider a wagon or people carrier.
3) Estimate luggage capacity from the segment. Compact and economy classes can be tight for multiple large cases, even if seating is fine.
4) Consider route and season. For winter mountain driving, look for an AWD or 4WD drivetrain letter rather than relying on appearance.
5) Confirm fuel expectations. If you prefer hybrid or electric, the fourth letter may indicate it, but also review the supplier’s vehicle description.
Remember that SIPP is about class, not a promise of a specific vehicle. “Or similar” is a standard part of car hire, so focus on the parts that affect comfort and usability: size, doors, transmission, drivetrain, and air conditioning.
FAQ
What if my voucher shows a car model but no SIPP code? Some documents list a popular model name for guidance, followed by “or similar”. If no SIPP is shown, use the listed features to infer it, focusing on doors, transmission, and air conditioning.
Does a SIPP code guarantee an SUV or a specific brand in California? It guarantees the class description only, not an exact vehicle. If the second letter indicates an SUV body style, you should receive an SUV or a closely comparable alternative.
Are automatic cars standard for car hire in California? Automatics are common, but not universal. Always confirm the third SIPP letter is “A”, “B”, or “D” if you require automatic.
How can I tell if my rental includes air conditioning? The fourth letter often indicates air conditioning, such as “R”, “D”, “H”, or “E”. If the fourth letter indicates no air conditioning, recheck the class details.
What should I do if the car I receive does not match the SIPP on my voucher? Ask the rental desk to explain the offered class and show the group equivalence. If key elements differ, such as transmission or doors, request an equivalent class to what your voucher specifies.
