As published in the October 7th Edition of North Shore Newspapers:
The history of the much loathed Route 347 is both fascinating and near tragic.  Once slated as a limited access route to serve Brookhaven as a diagonal Southwest/ Northeast route, the road became entrenched with encroaching development that strangled any possibility of increasingly needed improvement being made since the 1960s.  Drive on 347 between Nicholls Road and Jericho Turnpike for a quick planning lesson entitled “What not to do on a Primary Arterial Road”. The end result was a corridor that everybody hated, but nobody had the political will to actually implement a solution. The most frustrating part of the 347 saga is what could’ve been. Soon however, all of that is going to change.
Route 347 is a state route, thus the road is the State’s domain. Say what you want about the state, but the New York State Department of Transportation has been very busy for the last twelve years formulating how exactly they can approach this developmental quagmire that local government and shortsighted private developers got themselves, and everybody else into.  This week construction is starting on the section of 347 from Veterans Highway (454) to Route 111, and what is promised is, as the NYS DOT calls it, a “Suburban Greenway” with in sync traffic signals, more transit access points, streetscape improvements, a reduced speed limit of 45 miles per hour and, maybe more importantly, additional lanes in each direction. The reduced speed limit will be balanced out by increased traffic flow. Eventually the improvements will continue along the whole beleaguered corridor, in different phases of the project, terminating in Port Jefferson Station.  
What is interesting is that the DOT seems to be downplaying the biggest improvements along the route, as is the media reporting on the changes. The eventual elimination of on the ground, grade crossings at 347 and Nicholls Road, as well as 347and Jericho Turnpike (NYS 25) are long needed, and crucial to improving traffic flow on all of these routes, yet they are mentioned in passing.  At these interchanges, the DOT is proposing to build overpasses similar to the crossing at Nicholls and Middle Country Road in Centereach. The new interchanges may be further down the pipeline, but considering the history of the road, they are a huge accomplishment on the part of the DOT.
Anything that happens on 347 is an improvement, but from a planning standpoint is it enough? Well, no, because 347 needed these improvements ten years ago. It is sad that it took this long for any progress to be made on a road whose flanking development spiraled out of control, but it is everyone who is at fault. When development is to be stopped, NIMBY is the go-to weapon that communities use, but in reality, the story of 347 is much more complicated than that. It was not NIMBY that created 347’s traffic nightmares, but was the unrestricted development along the route. Each year more and more businesses had curb cuts and access to the road, essentially creating a new intersection. Whenever future development is proposed along the route, we should all look to the true traffic impacts of say, adding three big box stores or a medical office park right off of the corridor
The problem with 347 is so bad, and so prolonged, that regardless of academic ponderings of what could’ve or should’ve been, that the DOT is finally doing something. After many public outreach meetings and a plan that was formulated a in response to the road’s current usage, we are now presented with an improvement. In the past, 347 as a limited access, free flowing highway was (and still may be) necessary, but today it just cannot happen, so they did what they could: envisioned a 347 that was both a local and express road.  In the following years, we will all be inconvenienced by the delays caused by construction, but as you sit and wait, remember just how bad the conditions on 347 were, and how much they are going to improve if we are all patient and let the DOT do it’s much needed work.

http://www.northshoreoflongisland.com/Articles-i-2010-10-07-85603.112114-sub_Route_347_continues_its_ebb_and_flow.html