What Really Determines Used Car Prices: A Data-Driven Deep Dive

By shrijeetverma13 · July 14, 2026

We analyzed 5,500 vehicle listings to uncover what makes cars worth more or less. Model year is king—a 2024 vehicle sells for 40 times more than a 2005…

Looking at vehicle listings by location, GA stands out with the highest average selling price at $13,143. Two charts were generated to visualize this: one showing average selling price by location and another showing inventory volume (number of vehicles) by location, both covering the top 15 locations.

The Make and Model combination with the highest average selling price is the BMW X5, averaging $23,770 across 132 listings. It's closely followed by the Mercedes-Benz GLE ($23,292), Audi A6 ($23,160), Audi Q7 ($23,025), and Mercedes-Benz E-Class ($22,333).

Average selling price clearly declines as vehicles get older. Newer vehicles (2024 model year) sell for an average of $35,424, while the oldest vehicles (2005 model year) average just $883 — a 97.5% drop. The strong correlation of 0.96 between year and price confirms that model year is a major driver of value, reflecting typical depreciation patterns where vehicles lose value steadily over time.

Summary statistics were calculated for all 9 numeric columns in the dataset, including mean, median, min, max, and standard deviation. Two bar charts were created to visualize the mean values and variability (standard deviation) across columns, plus detailed data tables with all the computed statistics.

The automobile dataset contains 5,500 records across 18 columns covering vehicle details like make, model, year, engine size, mileage, horsepower, and selling price. A sample of the data shows a mix of brands (Mercedes-Benz, Hyundai, Volkswagen, Chevrolet, Toyota) with varying specs and prices. Numeric summaries show vehicles range from 2005 to 2024 model years, mileage from 100 to over 536,000, and selling prices from $500 to $86,692 (average around $12,320). Two charts were created: one showing the breakdown of column data types, and another showing the distribution of selling prices across the dataset.

Mileage is by far the biggest factor affecting Selling Price, with a strong negative correlation (-0.684) — meaning cars with higher mileage sell for noticeably less. Horsepower has only a weak positive relationship (0.078) and Engine Size shows almost no effect (-0.013) on price. The overall average Selling Price in the dataset is $12,320.

A correlation matrix was successfully computed and visualized as a heatmap showing the relationships between Fuel Efficiency, Engine Size, Horsepower, Torque, and Selling Price. The heatmap uses a red-blue color scale to make it easy to spot strong positive relationships (in red) and strong negative relationships (in blue) at a glance, with each cell labeled with its exact correlation value.

The analysis examined vehicle mileage data to detect outliers within each body type category using the IQR (Interquartile Range) method, and compared how outlier vehicles' selling prices differ from typical vehicles of the same body type. Data tables showing the outlier percentages and price comparisons by body type have been generated for your review.

The analysis grouped vehicles by Service History category and Accident History (0 vs 1+ accidents) to see how these factors jointly affect Selling Price. Two grouped bar charts were generated: one showing average Selling Price and another showing median Selling Price for each combination of Service History and Accident History. Supporting data tables with the exact average, median, and count values for each group were also produced, giving a detailed breakdown of how vehicle price varies across these categories.

Looking at all 8 Fuel Type and Transmission combinations, Electric/Manual vehicles offer the best balance of fuel efficiency and price, scoring 83.85 out of 100 on the balance metric. This combination averages 100 mpg-equivalent efficiency at a competitive $6,245 price. Hybrid/Manual ranks second (55.76 score) with 44.52 efficiency at $4,113, followed by Petrol/Manual in third (50.74 score). At the bottom, Diesel/Automatic scored lowest (20.66) due to its high average price of $14,168 despite moderate efficiency.