Understanding weather and road networks

Mastering U.S. Road Networks and Weather Patterns

Successful truck dispatching requires intimate knowledge of America's highway system and weather patterns. Understanding how roads are numbered, which routes are truck-friendly, and how weather affects different regions enables dispatchers to plan efficient, safe routes and avoid costly delays.

The U.S. Interstate Highway System

What is the Interstate System?

The Dwight D. Eisenhower National System of Interstate and Defense Highways (Interstate System) is a network of controlled-access highways that form the backbone of American freight transportation.

Key Facts:

Total miles: ~48,000 miles
Started: 1956 (Federal Aid Highway Act)
Completed: ~1992 (continually maintained and expanded)
Purpose: National defense, commerce, efficient travel

Why It Matters for Trucking:

✅ Truck-friendly: Designed for commercial vehicles
✅ No traffic lights: Controlled access only
✅ Consistent standards: Lane widths, grade limits, clearances
✅ National connectivity: Reaches all major cities
✅ Well-maintained: Federal funding for upkeep

Interstate Numbering System

How Interstate Numbers Work:

Even Numbers = East-West Routes

Pattern:

Lower numbers = South
Higher numbers = North

Major East-West Interstates:

I-10: Southern route (FL → CA via TX, AZ)
I-20: Southern mid (SC → TX via AL, MS, LA)
I-40: Central (NC → CA via TN, AR, OK, TX, NM, AZ)
I-70: Northern mid (MD → UT via PA, OH, IN, IL, MO, KS, CO)
I-80: Northern route (NJ → CA via PA, OH, IN, IL, IA, NE, WY, NV)
I-90: Northernmost (MA → WA via NY, PA, OH, IN, IL, WI, MN, SD, WY, MT, ID)

Odd Numbers = North-South Routes

Pattern:

Lower numbers = West
Higher numbers = East

Major North-South Interstates:

I-5: West Coast (CA → WA via OR)
I-15: Intermountain West (CA → MT via NV, UT, ID)
I-25: Mountain region (NM → WY via CO)
I-35: Central (TX → MN via OK, KS, MO, IA)
I-55: Mississippi Valley (LA → IL via MS, TN, MO)
I-65: Southeast to Midwest (AL → IN via TN, KY)
I-75: Southeast to Midwest (FL → MI via GA, TN, KY, OH)
I-85: Southeast (AL → VA via GA, SC, NC)
I-95: East Coast (FL → ME via GA, SC, NC, VA, MD, DE, NJ, NY, CT, RI, MA, NH)

Three-Digit Interstate Numbers:

Rule: First Digit Indicates Type

Even First Digit (e.g., I-270, I-495) = Loop/Bypass:

Connects back to parent interstate at both ends
Bypasses city
Example: I-495 (Capital Beltway around Washington DC connects to I-95)

Odd First Digit (e.g., I-110, I-580) = Spur:

Connects to parent interstate at one end only
Enters city or connects to another route
Example: I-110 in Los Angeles (connects I-10 to downtown)

Parent Interstate:

Last two digits indicate parent
I-270: Relates to I-70
I-495: Relates to I-95
I-610: Relates to I-10

Dispatcher Tips:

✅ Loops/bypasses useful for avoiding city congestion
✅ Spurs often lead to downtown areas (may have truck restrictions)
✅ Know your major metro bypasses (I-285 Atlanta, I-465 Indianapolis, I-275 Tampa)

U.S. Highway System (Non-Interstate)

U.S. Routes (e.g., US-30, US-50):

Characteristics:

Not controlled access (traffic lights, at-grade crossings)
Older system (predates Interstates)
Connects smaller cities and rural areas
Numbering similar to Interstates (even = E-W, odd = N-S)

Notable U.S. Highways:

US-20: Longest (Boston to Oregon)
US-30: Lincoln Highway (Historic transcontinental)
US-50: "Loneliest Road in America" (crosses Nevada)
US-Route 66: Historic (Chicago to LA, mostly replaced by I-40)

When to Use:

Toll avoidance (US-30 vs. PA Turnpike)
Interstate closure or congestion
Delivery to rural areas not served by Interstates

Trade-offs:

⚠️ Slower: Traffic lights, lower speed limits (55 mph vs. 70+ mph)
⚠️ Less truck-friendly: May have low bridges, weight restrictions
✅ Free: No tolls
✅ Scenic/Direct: Sometimes more direct than Interstate loops

State Highways:

Format: Varies by state (SR-99, State Route 1, Highway 71)

Characteristics:

State-funded and maintained
Highly variable quality and truck-friendliness
Essential for last-mile delivery to facilities not on Interstates

Dispatcher Caution:

Always verify truck restrictions
Check bridge clearances (some states have low bridges)
Rural state highways may be narrow, winding

Major Freight Corridors

Coast-to-Coast Routes:

Southern Route (I-10):

Jacksonville, FL → Los Angeles, CA
Via: Mobile, New Orleans, Houston, San Antonio, El Paso, Phoenix, Palm Springs
Advantages: Warm weather year-round, flatter terrain
Challenges: Summer heat (110°F+ in AZ), hurricane season (Gulf Coast)

Central Route (I-40):

Wilmington, NC → Barstow, CA
Via: Nashville, Memphis, Little Rock, Oklahoma City, Amarillo, Albuquerque, Flagstaff
Advantages: Balanced route, good services
Challenges: Winter weather (Flagstaff, NM mountains), wind (TX panhandle)

Northern Route (I-80):

Teaneck, NJ → San Francisco, CA
Via: Chicago, Des Moines, Omaha, Cheyenne, Salt Lake City, Reno
Advantages: Major cities, good infrastructure
Challenges: WINTER HELL (WY, NE, IA), mountain passes (Sierra Nevada, Rockies)

Northernmost Route (I-90):

Boston, MA → Seattle, WA
Via: Buffalo, Cleveland, Chicago, Minneapolis, Sioux Falls, Billings, Spokane
Advantages: Connects major northern cities
Challenges: BRUTAL WINTERS (MN, SD, MT), mountain passes

North-South Corridors:

East Coast (I-95):

Miami, FL → Houlton, ME
Via: Jacksonville, Savannah, Richmond, DC, Baltimore, Philadelphia, NYC, Boston
Advantages: Massive freight demand, major cities
Challenges: EXTREME CONGESTION, expensive tolls ($600+ for full length), weather (winter)

Midwest Spine (I-35):

Laredo, TX → Duluth, MN
Via: San Antonio, Austin, Dallas, Oklahoma City, Kansas City, Des Moines, Minneapolis
Advantages: Central corridor, balanced freight
Challenges: Winter (IA, MN), wind (OK, KS)

Southeast Corridor (I-75):

Miami, FL → Sault Ste. Marie, MI
Via: Tampa, Atlanta, Chattanooga, Knoxville, Lexington, Cincinnati, Toledo, Detroit
Advantages: Manufacturing corridor, Atlanta hub
Challenges: Atlanta traffic (I-285), winter (OH, MI)

West Coast (I-5):

San Diego, CA → Vancouver, BC
Via: Los Angeles, Sacramento, Portland, Seattle
Advantages: Major freight market, ports
Challenges: LA CONGESTION, mountain passes (Siskiyou, Cascades), winter (OR, WA)

Truck Restrictions on Highways

Parkways (NEVER TRUCKS):

What They Are:

Scenic roadways with low bridge clearances (9-10 feet)
Designed for passenger cars only
Common in New York, New Jersey, Connecticut

Examples:

Taconic State Parkway (NY)
Merritt Parkway (CT)
Saw Mill River Parkway (NY)
Garden State Parkway (NJ) - Some sections allow trucks, but confusing

Result if Truck Enters:

Bridge strikes (severe damage, injuries, deaths)
Fines: $5,000-$10,000+
Criminal charges possible
Insurance may not cover

Dispatcher Rule:

❌ NEVER route trucks on parkways
✅ Always use Interstate or U.S. Highway alternatives

Urban Truck Routes:

Many cities designate truck routes:

New York City, Chicago, Los Angeles, etc.
GPS may suggest non-truck routes
Use truck-specific GPS (Garmin Dezl, Rand McNally TND)

U.S. Weather Patterns: Regional Guide

Winter Weather (November - March)

❄️ Northeast (NY, PA, NJ, New England):

Heavy snow and ice - Common
Nor'easters: Major coastal storms
Temperature: 20-40°F, often below freezing
Impact: Road closures, delays, chain requirements (rare but possible)
Dispatcher Strategy:
- Monitor weather forecasts closely
- Build 24-48 hour buffer for appointments
- Avoid during major storm forecasts
- Experienced drivers only

❄️ Midwest (IL, IN, OH, MI, WI, MN, IA):

Heavy snow, ice, wind chills - Regular occurrence
Lake effect snow (MI, OH near Great Lakes)
Temperature: 10-30°F, frequent sub-zero
Blizzards: Can shut down I-80, I-90, I-94
Impact: Major delays, road closures, dangerous conditions
Dispatcher Strategy:
- Minnesota, Wisconsin, Dakotas = most severe
- I-80 (IA, NE) and I-90 (MN, SD) are high-risk
- Never schedule tight appointments in Jan-Feb

❄️ Mountain West (CO, WY, MT, ID):

MOST DANGEROUS WINTER DRIVING
Mountain passes close regularly
Chain laws strictly enforced
I-70 (CO), I-80 (WY), I-90 (MT) = frequent closures
Temperature: 0-30°F in mountains
Impact: ROAD CLOSURES lasting hours to days
Dispatcher Strategy:
- ⚠️ Avoid if possible (use southern I-10 route)
- If must go, allow extra 2-3 days for weather delays
- Require chains on truck
- Monitor COtrip.org (CO), WyoRoad.info (WY)

🌨️ Pacific Northwest (WA, OR):

Moderate snow in mountains (Cascades, Siskiyous)
Rain, ice in lowlands
I-5 mountain passes: Snoqualmie (WA), Siskiyou (OR/CA border)
Impact: Pass closures, chain requirements
Dispatcher Strategy:
- I-84 (Columbia River Gorge) = ice common
- Chains required on I-5 passes

⚠️ South (TX, Southeast):

Rare winter weather, but VERY DANGEROUS when it happens
Ice storms, freezing rain - Drivers not experienced
Texas Freeze (Feb 2021): State shut down for week
Atlanta Ice Storm: City paralyzed
Impact: When it happens, everything stops
Dispatcher Strategy:
- Don't underestimate southern winter storms
- Ice more dangerous than snow (untreated roads)

Summer Weather (June - September)

🔥 Southwest Desert (AZ, NV, Southern CA, West TX, NM):

EXTREME HEAT - 110-120°F common
I-10 (AZ), I-15 (NV), I-40 (Mojave) = hottest
Impact:
- Tire blowouts (heat + pavement = failure)
- AC failures (dangerous for drivers)
- Reefer units work harder (higher fuel costs)
- Pavement can buckle
Dispatcher Strategy:
- ✅ Ensure trucks have good tires
- ✅ Avoid afternoon driving if possible (hottest 2-5 PM)
- ✅ Verify reefer maintenance before summer loads
- ⚠️ Phoenix, Las Vegas, Desert = highest risk June-August

🌧️ Gulf Coast & Southeast (TX, LA, MS, AL, FL, GA, SC):

Hurricane Season: June 1 - November 30 (peak Aug-Oct)
Impact:
- Ports close (Houston, New Orleans, Mobile, Savannah, Jacksonville)
- Roads flood
- Mass evacuations (I-10, I-95 reverse lanes)
- Freight halts for days before/after storm
Dispatcher Strategy:
- Monitor National Hurricane Center
- Avoid Gulf Coast 48 hours before landfall
- Evacuate trucks from storm zones
- Emergency freight after storm = premium rates

🌧️ Thunderstorms & Tornadoes (Midwest, Plains, South):

Tornado Alley: OK, KS, TX, NE
Severe thunderstorms: Spring/Summer
Impact:
- Brief but intense delays
- Road closures for tornado warnings
- Wind damage, hail
Dispatcher Strategy:
- Monitor radar during spring/summer
- Drivers should pull over during severe storms
- I-35, I-40, I-70 through tornado zones

💨 Wind (High Plains):

Wyoming I-80, New Mexico I-40, West Texas I-10/I-20
Sustained 40-50 mph winds
Impact:
- High-profile vehicles (empty trailers) can tip over
- Light loads dangerous
- Road closures for high wind
Dispatcher Strategy:
- Warn drivers of wind forecasts
- Slow down or stop if winds exceed 50 mph
- Flatbeds/empty vans most at risk

Year-Round Weather Challenges:

California Fog (Central Valley):

I-5, CA-99 through Fresno, Bakersfield
Tule fog (dense, thick) - Nov-Feb
Zero visibility
Impact: Multi-vehicle pileups, road closures
Strategy: Avoid driving in fog, wait it out

Mountain Passes (Year-Round):

Grades, curves, elevation
Runaway truck ramps (brake failures)
Fuel economy drops climbing grades
Key passes: Donner (I-80 CA), Eisenhower (I-70 CO), Monteagle (I-24 TN), Cabbage (I-80 PA)

Weather Resources for Dispatchers

Road Condition Websites:

National:

511 - Dial from anywhere for state road conditions
weather.gov - National Weather Service

State-Specific:

California: QuickMap.dot.ca.gov
Colorado: COtrip.org
Wyoming: WyoRoad.info
Pennsylvania: 511PA.com
New York: 511NY.org
(Every state has official DOT road conditions site)

Weather Apps:

Weather Underground:

Hyperlocal forecasts
Severe weather alerts

RadarScope:

Professional radar app
Tornado warnings, severe storms

Windy.com:

Wind forecasts (critical for high-profile loads)

Trucker-Specific:

Trucker Path:

Road conditions crowdsourced from drivers
Weigh station status
Parking availability

Weather.com Trucking:

Routes overlay with weather
Forecast along route

Route Planning Best Practices

Winter Route Selection:

Preferred: Southern Routes (Nov - Mar)

✅ I-10 over I-80/I-90 (avoid mountains and snow)
✅ I-40 over I-70 (lower elevation, less snow)
✅ I-20 if going Texas to Southeast

Avoid: Mountain & Northern Routes (Nov - Mar)

❌ I-80 (WY, NE) - Extreme winter weather
❌ I-90 (MT, WY, SD, MN) - Brutal cold and snow
❌ I-70 (CO) - Mountain pass closures

Summer Route Selection:

Acceptable: Northern Routes (May - Sep)

✅ I-80, I-90 - Good weather, no snow
✅ I-70 - Mountain weather is nice

Caution: Southern Desert Routes (Jun - Aug)

⚠️ I-10 (AZ), I-15 (NV) - Extreme heat
⚠️ Early morning/evening driving preferred
⚠️ Verify truck/reefer condition

Hurricane Season (Jun - Nov):

Monitor Forecasts:

If hurricane approaching Gulf Coast or Atlantic Coast:
- ❌ Don't dispatch new loads into storm zone
- ✅ Evacuate trucks 48 hours before landfall
- ✅ Wait for all-clear before returning

Year-Round Considerations:

Check Before Every Dispatch:

✅ Current weather conditions on route
✅ Forecast for next 48-72 hours
✅ Road conditions (construction, closures)
✅ Mountain pass status (if applicable)
✅ Seasonal hazards (fog, wind, heat, ice)

Build Buffer Time:

Weather delays are inevitable
Add 10-20% extra time for long hauls
Never schedule "tight" appointments in winter

Speed Limits by State (General)

Interstate Speed Limits for Trucks:

70-75 mph (Western states):

Texas, Montana, Idaho, Wyoming, Utah, Nevada
Fastest truck speeds in nation

65-70 mph (Most states):

Majority of Midwest, South, some West

65 mph (Truck limit, cars higher):

California, Oregon, Washington
Illinois, Michigan

55-60 mph (Slowest):

Some urban areas
Work zones

Differential Speed Limits: Some states have lower limits for trucks than cars:

California: Cars 70 mph, Trucks 55 mph (Interstates)
Oregon: Cars 65-70 mph, Trucks 55-60 mph

Dispatcher Note:

Factor speed limits into transit time calculations
Trucks in CA are slower than other states
Work zones can drop speeds to 45 mph

Conclusion

Mastering U.S. road networks and weather patterns is essential for efficient, safe dispatching. Knowledge of highway numbering, major corridors, and seasonal weather hazards enables dispatchers to:

✅ Plan optimal routes based on season and weather
✅ Avoid dangerous conditions that risk driver safety
✅ Minimize delays by anticipating weather impacts
✅ Set realistic transit times factoring in conditions
✅ Communicate proactively with drivers and customers

Key Takeaways:

Interstate Numbering:

Even numbers = East-West, Odd numbers = North-South
Lower numbers = South/West, Higher numbers = North/East
3-digit: Even first = loop, Odd first = spur

Major Routes:

I-10: Southern coast-to-coast (warm year-round)
I-40: Central route (moderate)
I-80: Northern route (avoid in winter)
I-95: East Coast (congestion, tolls)

Winter Strategy:

⚠️ Avoid: I-80, I-90, I-70 (mountains) Nov-Mar
✅ Use: I-10, I-20, I-40 (southern routes)
✅ Build extra time for weather delays
✅ Monitor road conditions daily

Summer Strategy:

⚠️ Caution: I-10 (AZ), I-15 (NV) extreme heat
⚠️ Hurricane season: Avoid Gulf/Atlantic coast during storms
✅ Northern routes excellent (I-80, I-90, I-70)

"The best route isn't always the shortest—it's the safest, fastest, and most reliable given current conditions."

Continue Learning:

Master road networks and weather to keep freight moving safely and on time. Continue your education at Carriversity.