My new site http://carpricegraph.com generates zoomable graphs of car prices with up-to-the-minute data pulled from craigslist.

]]> http://danrathbone.com/2011/05/new-project-carpricegraph-com/feed/ 0 http://danrathbone.com/2010/11/what-price-for-a-used-suv-scraping-craigslist-helps-me-decide/ http://danrathbone.com/2010/11/what-price-for-a-used-suv-scraping-craigslist-helps-me-decide/#comments Mon, 29 Nov 2010 03:32:03 +0000 rathbone1200cc http://danrathbone.com/?p=668 The snowboarding season has arrived in the Pacific Northwest and I’m hoping to buy an SUV to help me get up to the mountains.  As a good computer scientist, I want some data to help inform my selection of a used car.  To that end I wrote a little program that scraped some pricing data from Seattle’s craigslist, and here’s what I found.

Craigslist car ads last for one week, and I narrowed my search to three models of SUV.  There were about 1700 listings that fit these criteria.  My little program, written in F#, was able to extract pricing and model-year data on about 1500 listings.  Mileage data was missing from many listings, but I managed to parse out about 280 usable numbers.  The data shows some interesting trends, but there’s a caveat: this data displays listing prices – the asking price for these vehicles – which is different (probably higher) than the eventual sale prices of the vehicles.  Additionally, craigslist ads are not externally verified, so there’s no guarantee that the sellers listed mileage data truthfully.  With that said, here’s some pretty charts:

Model-year vs. Price

Naturally, vehicles depreciate as they get older.  This data indicates that these SUVs depreciate about $2500/year for the first 10 years, and after that they retain their value.  One can extrapolate that the buyers and sellers in this market expect that these SUVs will operate reliably for the first 10 years, but after that the value of a vehicle must account for recent or expected replacement of mechanical components.  Indeed, many of the listings for older vehicles mention rebuilt engines or other major maintenance.

It appears that a Toyota 4Runner retains its value better than the Nissan Pathfinder, which in turn retains its value better than the Jeep Grand Cherokee.

Mileage vs. Price

Vehicles depreciate as they’re driven.  This chart indicates that the relationship is roughly proportional.  The three models under consideration seem to depreciate $7500 for every 50,000 miles, but the correlation is not exact.

To return again to my personal situation, I’m simply hoping to find the best value for my money.  I see that the chart of price-depreciation-per-year regresses much more neatly than price-vs-miles, so I’m wondering if I look at older vehicles with low miles, I’ll find a better-than-average value.  Based on this data, my strategy is to find a 10 year old 4Runner with less than 100,000 miles for around $11,000.  If I’m lucky, the thing will run for a few years without mechanical failure and retain most of its value, which would yield very good value-for-money.  If I’m unlucky and I need to drop in a few thousand dollars on mechanical repairs, then I still expect this will yield better value-for-money than a newer car that depreciates more rapidly as the years go by.

Use your mousewheel to zoom and drag to pan along the images. Be sure to take a look in fullscreen mode – hit the little button in the top right of the player below.

Be sure to try the full-screen view!

Anecdotes swirl around the Cathedral of Seville; they explain the original intention for its construction.  Though the details vary, the general theme is this: the designers wanted to build a cathedral so high and so beautiful that anyone who sees it instantly either goes mad or places all their faith in God.  I am an atheist.  After seeing the Cathedral, I still don't believe in God, I might be crazy, and I admit that it's a magnificent building.

Sevilla's Cathedral is the third largest in the world, by area, behind St. Peter's Basilica and another church in Brazil.  Unlike St. Peter's Basilica, which represents to me the hypocrisy of religion, Seville's cathedral holds the bones of good old Christopher Columbus, which are worth a few points in my good books. 

Everything about the place is huge and expensive.  The alter is easily the biggest gilt thing I've seen, towers at least 60 feet tall.  The organs are massive.  La Giralda, the bell tower, rises 322 feet.  Its internal ramps were built wide enough to allow a Spaniard to ride on horseback up through the inside to ring the bells.  Impressive views are to be seen from the top.    Of course, the treasure is invaluable, and there's even a hanging crocodile.

Though Alcázar and Alhambra share a similar architecture, their situation is entirely different.  Alhambra watches over its city, perched on a hill. Alcázar is centered in Seville, surrounded by the city, and adjacent to the magnificent and later-built Christian cathedral.  While Alhambra dominates Granada, in Seville, Alcázar plays second fiddle.

Though overshadowed, Alcázar cannot be overlooked.  One has not truly visited Seville until one has visited Alcázar, as the story of the palace is the story of the city, written in stone.  Muslim style rooms lead directly into Christian style rooms, showing the same clash of culture as in the Mezquita in Cordoba.  These remarkably disparate styles indicate the abrupt change in religion and rule, they are the scars of the Reconquista, the architectural equivalent of scar tissue.

In visiting Alcázar, I was most surprised by the fantastic gardens. Truly, they’re nicest I’ve seen.  Enclosed by massive stone walls, partitioned by smaller internal walls, each part has a distinct style.  I admit that I do not know enough of landscape design to associate these styles with their Moorish and Christian history, but in spite of this, or perhaps because of it, I carried along a sense of wonder as I walked these perfect grounds.

The palace and its rooms are marvelous, to be sure, but it’s a stretch to complete the picture.  I can hardly imagine the people and furniture that they once contained. The gardens, however, see their blooms renewed year after year, and surely they could never be more glorious than when I saw them, allowing me to enjoy views of this beauty in the same manner as so many visitors for centuries before me.

Each procession is organized and staged by a brotherhood, a society established around a particular church, and there are dozens.  The anatomy of a procession has these parts: Nazarenos, Pasos, and marching bands.  The Nazarenos are the brothers marching. There may be dozens, there may be thousands; they conceal their individual identities with uncomfortable pointy-hat costumes.  The pasos are sculptures depicting bible scenes and the Virgin Mary. Sometimes gilt, always heavy, they are carried from below by harnesses over the necks of strongmen crushed beneath.  The marching bands, composed of horns or percussion, announce the procession with music of alternating pride and sorrow.

Personally I was fascinated by this solemn tradition.  I saw the sad, burdensome rituals were relieved by the spectators’ response.  In the middle of a city entangled in parades there was nothing I or anyone could do but stop at a cafe and watch. The Spaniards and the tourists and I would gather in the streets, drink beer and chew olives at all hours of the day and night, and greet the processions with laughter, cheers and song, or silence – and occasionally tears.

Occasionally the processions would stop to rest, and in the still silence and old man or woman would sing sad Spanish folk music from a window above. In this manner, and with such an audience, the processions limped along all week like a wounded serpent, until the final day, when the last brotherhood marched in total silence, and at the end of their trail, the festival died.

Quickly I found a tailor shop.  I marched my way in, wearing my comfortable but threadbare blue jumper, and I left the shop wearing a brown lightly-striped single-breasted travel blazer called the “Traveltino”.  This was a turning point in my trip through Europe.

Immediately I learned the extent to which people judged me based on my appearance.  No longer was I a foreigner, a stranger to avoid.  In the eyes of my Spanish neighbors, Traveltino and I were locals, born and raised in Seville, whom you could stop and ask directions, since we assumedly (but incorrectly) spoke fluent Spanish and knew our way around.  This trend continued even after Seville – the only change was that I, after leaving Spain, was apparently Italian.

Seville is the city richest in Andalucian culture. I spent a week there, watching the festivities and visiting the city’s historical sites.

The highlights of my visit were watching Holy Week parades and marveling at Alcazar and the magnificent cathedral, all of which I’ll describe in further posts.  In the mix of the history, culture, and people, I managed to enjoy some great coffee, spot this sweet Lambo, explore the many plazas and streets, catch this woman sleeping in her shop, drink at this crazy catholic bar, notice these ornate street lamps, stumble upon some walled gardens, and walk the Guadalquivir river at night.

In the short term, before I start my new job, I’ll take a few weeks to reconnect with friends and ride my motorcycle around the Pacific Northwest.