CHICAGO—Many drivers hung onto their old cars during the recession, providing a boost to the nation's auto parts sector. Net lease investors were then drawn to these properties, pushing down their cap rates to historic lows. And even though the worst of the economic times seems past, auto parts remains one of the more popular net lease options. Cap rates for the single tenant net leased auto parts store sector sank to 5.98% in the fourth quarter of 2015, a decrease of 27 bps from the previous year, according to a new study from the Boulder Group , a net lease firm in suburban Chicago. This decline slightly outpaced the overall net lease retail market which compressed by 25 bps over the same time period. “Clearly we are no longer in a deep depression, but people are still being more conservative when it comes to big ticket items like cars,” Randy Blankstein , president of Boulder, tells GlobeSt.com. A recent report by R.L. Polk & Co. and IHS Automotive shows that the average age of vehicles on the road has increased slightly to 11.5 years. The researchers expect the average age to continue increasing through 2018. For its new study, Boulder surveyed deals for Advance Auto Parts , AutoZone and O'Reilly Auto Parts stores because these three accounted for the highest percentage of transactions involving auto parts tenants. One of the reasons net lease investors like auto parts stores so much is that, along with dollar stores, they are one of the few investment grade options priced below $2 million. And when compared to dollar stores, auto parts stores are likely to be located in primary and secondary markets near major retailers. Cap rates for Advance Auto Parts, AutoZone and O'Reilly Auto Parts compressed to 6.35%, 5.75% and 5.68% respectively in the fourth quarter. Advance Auto Parts properties tend to have higher cap rates due to a greater supply of older stores with shorter term leases when compared to the others. In the fourth quarter of 2015, Advance Auto Parts properties with less than 10 years of lease term remaining made up 50% of the overall supply. In comparison, leases of less than 10 years accounted for only 29% and 20% of all O'Reilly Auto Parts and AutoZone properties on the market. In addition, Advance Auto Parts only signs 15-year leases for new construction properties, and O'Reilly and AutoZone typically sign 20-year leases. “Transaction volume in the auto parts sector should remain active as investors continue to seek this asset class due to the positive outlook and fundamentals associated with the auto parts industry,” according to the study. “Recently constructed properties with long term leases should continue to be in the highest demand as these assets are the most sought after amongst 1031 buyers due to their lease term duration.”