Most recent highways you've traveled on for the first time

[golden eagle]

It can be as a driver or passenger. Here's mine:

Interstate: I-565 (2012)
U.S.: 50 (2014)
State: TN 385 and MS 305 (last weekend)

[jp the roadgeek]

Interstate: 10, 88 (E), 110 (MS), 610 (LA), 2014

US: 90,  2014

State: CT 349, NY 28/80/166, 2014

[CNGL-Leudimin]

Incidentally, all of my most recent highways travelled on for the first time were grabbed in my mid-April trip

Interstate-like: the expressway section of SO-20 (I had been on SO-20 before, but only on the super 2 section).
US-equivalent: N-121-C.
State-equivalent: NA-125, NA-134, CL-116, A-116.

However, the 'Interstate-like' and 'State-equivalent' may change by the end of current month.

[hotdogPi]

I-293
US 50
MA/NH 12
MA 140
NH 114
NH 103
I-89

[1995hoo]

Interstate: I-795 in North Carolina (last December on our way south for Christmas)
US: I think US-117 in North Carolina after hitting the end of I-795 on the same trip
State route: SC-31 near Myrtle Beach later the same day after the previous two noted above. 

[Mapmikey]

Most recent new travel (all on 5/30/15 or 6/3/15)...

Interstate: I-579
US Route: US 62 Warren PA to I-190 near Buffalo
State: NY 354 from US 62 to I-190
International: ON 405

Mike

[PHLBOS]

Courtesy of the recent Scranton/Wilkes-Barre Meet (& aftermath):

I-476 (north of I-80)
I-81 (north of I-78)
US 222 (between PA 61 & I-76)

[Bickendan]

WA 502
WA 503
WA 432
WA 4
WA 411
OR 202
OR 104
OR 104S
OR 103

[bzakharin]

As a driver:
I-87 (2014, first ever time driving into CT)
US 40 (2015, bypassed jam on the Atlantic City Expressway)
NJ 168 (2014, bypassed jam on NJ 55)
PA 332 (2012, my job search took me to Newton, PA)
DE 3 (2012, my job search took me to downtown Wilmington)

As a passenger:
I-83 (2012, bypassed jam on I-95 in Maryland)
US 40 / US 13 (2012, bypassed different jam on I-95 in Maryland)
NJ 133 (2012, bypassed jam on the NJ Turnpike)
PA 940 (2012, my phone died while on vacation, so had to go into Mount Pocono, the nearest AT&T Store)

[wphiii]

2DI: I-30 (for about 2 miles, last May, helping my brother move to Little Rock)
3DI: I-865 (last Thanksgiving en route to Chicago, immediately preceded by I-465)
US: U.S. 421 (this is lame, but its concurrency with I-465 makes it the most recent U.S. highway I was technically on for the first time)
State: PA913 (literally yesterday, along with PA655)

[hbelkins]

The portion of KY 21 east of US 421, a couple of weeks ago.

[SignGeek101]

Highways overseas for me back in 2014 were the most recent.

Japan National Route 357
And others (I was tired and don't remember which ones)

Highways in Indonesia when I went there in 2014.

In the US (2012 trip to New York)
I-81
I-95
US 1
US 50
And others, again don't remember.

2011 trip
I-75 from Sault Ste Marie to Mackinaw City

Canada (2014 Trip) If I been on these before, I was very young and didn't remember.
BC 99
BC 91
TC 1 (In BC)

2011 Trip
ON 17
ON 69


Edit: Remembered a couple.

[kurumi]

April 2015: I-229, IA 60, MN 23, US 169, US 34
August 2014: HI 92, 72, 8930, 65

[sipes23]

State: Wyoming 487, clinched in one go
US: US 26
Interstate: I-180, awww yeah

[DandyDan]

Interstate: I-155 IL, from its north end to US 136 (only minutes before I witnessed a fatal traffic accident).
US Route: I believe it is US 231, from Crown Point, IN to its north end.  Both of these were in June 2012.
State: Iowa 122, in March.  My most recent new Nebraska highway is S13K, the spur to Weeping Water.  The most recent numbered NE highway is NE 32 (if the overlap with US 275 in West Point doesn't count).

[HazMatt]

All these from a trip up to Ocean City and parts of Delaware last month.

I-664 (US-58 concurrency)
US-50 (Ocean City to Bowie)
VA-207 (US 301 cutover to I-95)

[xcellntbuy]

With my new home in Milledgeville, GA there are many:

Interstates 20 and 285
GA 400
GA 212 (the nice quiet, forested way to Atlanta and its eastern suburbs)
GA 57 (almost no traffic in the pine-filled hills of clay and kaolin)
GA 22
GA 49
GA 16
US 441 (a whole different world from south Florida)
Interstate 16

[Kacie Jane]

Interstate: I-275 in Tampa, May 2014
2di: I-77 and I-26, February 2014
US: US 97 Alt. (WA), April 2015
If we don't want to count bannered routes, then I'm not sure I could pinpoint it, but probably US 17 and/or 441 around Orlando, but I'm not sure which month (2013-14) would be the first.  (And not US 92, I would have had that well before the other two.)
State: NV 373 and 374, CA 127 and 190 (and a couple of urban NV routes in Las Vegas) May 2015
Washington state: 153, April 2015

[Sam]

I-79 in PA and WV,
US 29 in VA
April 2015

[theline]

This pretty easy for me, since I visited SoCal last fall for the first time in almost 50 years.

CA-1, on the part between LAX and Malibu. I may have been on part near LAX during my last visit, but only as a passenger. I was too young to drive. Was it even called CA-1 back then? There is a near-tie here with several other California routes, like CA-2 (Santa Monica Blvd.), though nobody seems to call them by their route numbers.

I almost said US-101, but I drove the part near Olympic National Park years ago. Are there any other US routes in the LA area, since 66 was decommissioned?

I-210: this was probably the last of several interstates that I was on for the first time during this trip. We went to Burbank and Pasadena.

[corco]

This is somewhat tricky (but also very easy), in light of my recent trip:

Interstate- 495 NY
US Route-  US 301
State Route- I believe MD 2, with Laura and Mike in tow

[roadman65]

Last week I finally got to travel on I-95 between Rivera Beach, FL to Stuart, FL and from Fort Pierce to Vero Beach.
I also clinched US 98 from US 27 near Sebring, FL to US 441 in Okeechobee, FL as well as FL 710 from its western terminus in Okeechobee to Congress Avenue in Rivera Beach.

In a few weeks I will be clinching I-35 from the Dallas/ Fort Worth Metroplex to Wichita to finally add some more I-35 mileage to my clinch list.

[roadman]

Didn't get a chance to drive the Bald Eagle to Bellefonte section of I-99 until 2012.

[CtrlAltDel]

On my trip to the Southeast last month, I got a whole bunch of new Interstates, to wit:
4, 10, 12, 16, 20, 26, 64, and 75.

How I managed to live in Southern California for ten years without touching the 10 is beyond me.

[Eth]

Interstate: I-105 (CA) in 2013? I think that trip came after my first time on I-24.

US: US 378 (December 2014), though that feels like cheating since it was just jumping off I-20 for a bite to eat. If we don't count that...I could say US 72 in December 2013 on a technicality due to a bridge being out and it effectively being routed onto I-24 in the meantime. And if that also doesn't count, my best guess would be US 123, though I'm not even entirely sure of the year on that one. Either 2012 or 2013.

State: I think it would be SC 700 (December 2014), unless I hit that on a previous trip to Charleston; I can't remember. If so...maybe SC 171 on the same trip? If I already had that one too, then the answer is definitely SC 39, also on the same trip.