It is no surprise our nations infrastructure as a whole received a failing grade on a recent national inventory report card. The Interstate was first authorized and heavily funded starting in 1956. Many of the original alignments built in the following years through the late 1960's still remain as narrow two highways lanes each way while urban portions have been expanded 2 and in some place 3 times since inception.
In 1968 the US population was 168 million. Today there are over 320 million US citizens. Fundings amounts are up but percentages have declined among other national challenges. User delays continue to outpace expansion despite new funding sources such as private public partnerships (so called P3 agreements).
The USDOT interstate system is managed by the Federal Highway Administration (FHWA) which delegates local responsibility to the State DOT's. Most states like Indiana have to self fund the maintenance for the existing infrastructure and can only add capacity with matching federal funds. Even though the states may only need to contribute 20% of the project cost (with the FHWA contributing the remaining 80%) funds are too scarce to perform all of the needed repairs. This forces local DOT's to prioritize projects with some locals always being neglected.
Aware of the problem from the local DOT's politicians are looking to develop sustainable solutions with alternative funding sources.
The attached image is a picture I took a couple of years back while I was out on a job site on I-70 just east of Indianapolis IN. The project was fortunately a much needed added travel lanes project that increased safety with larger shoulders, additional travel lanes, median barrier wall and better drainage.