At the paver itself, “it’s mainly the visibility issue,” says Humphrey. “The mix goes through the paver the same way, grade and slope control operates exactly the same way, it’s just that people can’t see as well. For example, the operator may not be able to see his steering guide with we’ll just say conventional balloon lights on a paver. We may have to take a separate light – a spotlight – and focus it on the steering guide, so that the operator can clearly see that when matching a joint.

“We may also want to have a light that shines directly into the auger chamber, so that the screed operators can clearly see the head of material. They’re trying to control that to cover one-half of the auger and fill-in in front of the extension to make sure there are no voids,” he says. “Typically, that area is kind of dark even with conventional lighting, so a spotlight in that area is very helpful.”

It’s always a challenge, says Volvo’s Sunkenberg, for equipment manufacturers to keep up with lighting requirements that vary by jurisdictions. Or, as Humphrey puts it, “sometimes the local requirement for lumens actually gets in the way of clear visibility.” Personally a fan of the inflatable balloon lights that can be attached to the paver or stand alone, Sunkenberg has seen scenes throughout the country that range from a single light fixed to a paver, to long rows of portable lights stretching many thousand feet up and down the road, to ballasted high-intensity “warehouse” lights literally blasting harsh brightness onto the job. “I’d say more often than not, contractors are building their own, customizing their own,” says Sunkenberg, whose company does offer a lighting kit for its paving equipment.

He doesn’t sell balloon lights, but Terex Roadbuilding’s Rieken is likewise a fan, “because they are so easy to attach to the paver, they don’t glare and they just light the world up. They inflate when you plug them in, and I just think they’re slick,” he says. “I don’t have any stock in them, I don’t sell them; I just like them. I just think they provide a really good lighting system on the paver itself. With other lights, you’ve got to be careful how they are aimed, so that they don’t create a glare, not only for the people on the jobsite, but for anybody driving by. The balloons light the world up without that glare, so I’ll give them a plug,” adds Rieken, specifically mentioning the Airstar brand of balloon lighting products.

“The facts that balloon lights are glare-free, shadow-reduced, portable and that they spread their light all around in a 360-degree circle make them so popular,” says Ingmar Hansen, vice president of Powermoon Enterprises Ltd., a company which offers a line of modified balloon products. An “umbrella system” is designed to prevent the Powermoon lights from accidently deflating, says Hansen.

Along with the more uniform heating of the new electric screeds available on pavers, “there’s power on board at the paver to light the world up around the paver itself,” says Rieken. “We designed ours knowing there would be a lot of night paving going on. The rule of thumb is that it takes about 1 kW per foot to heat a screed, so on our Stretch 20 screed we have a 34-kW genset. So, you can add extensions and go wider, up to 26 feet if you choose, but still have plenty of kW left to have the lights on at the same time you’re heating the screed.”

Especially when working with high-intensity lights, the powering of lighting systems at the paver is an issue that equipment manufacturers have had to deal with, says Volvo’s Sunkenberg. “We need a very stable, consistent power source, which on a machine is difficult because you have horsepower fluctuations, or the engine lugs down, or you have hydraulic surge and hydraulic delays. It’s certainly a challenge from an equipment standpoint,” he says. “Our highway-class machines have outlets as standard equipment. You can boast that you’ll plug other things other than lights in there, but 99 percent of the time that’s what they’re there for. Occasionally, a guy will plug a power drill in because maybe he doesn’t have a service truck right there and he’ll use the paver outlets for alternative power, but it’s really for night lighting.”

Man with a plan

Saving a few minutes a few times over a night shift is really what the intricate planning Humphrey espouses is all about.

Case in point: “Vibratory compactors typically will need to resupply the water spray system once during the shift. If I’m going to refill the water spray system in, let’s just say, five hours, I want to know where I’m going to be on the project five hours from the start, and that’s where I’m going to have my water truck waiting,” he says. “I don’t want to need to have somebody run back to the start of the job and bring the water truck up to that point. I want to have it there already. It’s a small detail, but maybe that saves you 10 minutes. Those are the things I’m talking about – this planning, planning, planning.”

Not only adding a truck or two to the job cycle, but when to have them can be a timesaver, says Humphrey, citing a three-lane paving job in which the high-speed lane is paved for 1,500 feet, the crew then picks up, backs up and completes the middle lane for the same distance, and then ditto for the right lane. He calculates that 18 trucks hauling an average of 22 tons are going “to get me this distance. What I’ll try to do is make sure that I’ll have those 18 trucks show up to me in a tightly staggered pattern, so that I don’t have any stops – zero stops – especially during that first lane pull. I might gain a little bit on my production the first pull. I’m really going to try to plan that I have enough trucks to get me through that first pull without ever having the possibility of a stop.”

The theory, says Humphrey, is to get through the first third of that particular phase of the project in less than one-third of the phase’s allotted time. “I balance plant output, trucking, paving speed and compaction, so that in that first pass, I can go as fast as I can get the mix to it, without stopping and without outrunning the compactors. Then I’ve got myself a little breathing room moving forward.”

The vehicle volume factor

Ironically often the political reason for paving at night, reduced traffic, actually represents an advantage to efficient night paving, “because the traffic is what really hinders continuous paving,” says Terex Roadbuilding’s Rieken. “During the day, you might have a plant that has sufficient production, you might have adequate trucks, but the traffic still might hinder the flow of trucks to and from the jobsite, so the night paving if anything probably lends to the success of the continuous paving process, because there is less traffic.”

Says Humphrey: “The paver itself doesn’t care how fast you pave, as long as you’re consistent and don’t have long stops … and the compaction process can match you. So, you plan all that before you go to work. You make the calculations.” Adds Sunkenberg: “If you’re on a continuous paving job at night and the paving train stops, they’re upset, because the profilograph will pick up a stop and it will count against their final score and will ultimately cost them money.”

On the con side of the night paving equation is increased cost, says Rieken. “To ensure the safety of the paving crew and the operation, and of the people driving on the road, it takes more people, more equipment to make that happen, so there is a cost incurred that would probably be the biggest downside of doing it at night.” Which leads to another suggestion from the veteran trainer Humphrey: “Fatigue plays a huge role in night paving. I’d suggest trying to figure out a way if I can overstaff by one person. ‘Can I give people a chance to actually stop work for a minute, get a cup of coffee and stagger out a little bit, so they don’t get quite as fatigued, lose their focus, because that’s when mistakes happen?’