Drive carefully if you are venturing through the MassPike East toll plaza near Route 128. Toll lanes are being reconfigured over the weekend to improve traffic flow, according to a press release from the Massachusetts Turnpike Authority. Drivers can expect delays Saturday while road crews work to install new signs and stripe the roadway. The new configuration, which regular commuters will see Monday, will direct motorists paying cash to the center of the toll plaza and Fast Lane drivers mostly to the left side of the plaza, according to the release. To receive email updates on traffic changes and road restrictions, sign up for e-Traveler at www.masspike.com.