Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Image Optimization
Action
31 images, 0 KB saveable
REVIEW
31 images, 0 KB saveable
Warning::
!
https://www.transportation.gov/themes/custom/dot_c... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.transportation.gov/themes/custom/trans... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
31images2.9 MB
0oversized-0 KB
28legacy format
15missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
8 fonts (400 KB)
PASS
8 fonts (400 KB)
Info::
i
8 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
8
400 KB total
Render-blocking
0
of 8
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
6xK3dSBYKcSV-LCoeQqfX1R...woff2swap
Size15 KB
Load time21 ms
Start853 ms
RiskFOUT — text flashes from fallback to web font
fa-solid-900.woff2woff2swap
Size153 KB
Load time39 ms
Start853 ms
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
S6u9w4BMUTPHh6UVSwiPGQ3...woff2swap
Size14 KB
Load time16 ms
Start853 ms
RiskFOUT — text flashes from fallback to web font
6xKydSBYKcSV-LCoeQqfX1R...woff2swap
Size14 KB
Load time20 ms
Start854 ms
RiskFOUT — text flashes from fallback to web font
6xKydSBYKcSV-LCoeQqfX1R...woff2swap
Size15 KB
Load time29 ms
Start854 ms
RiskFOUT — text flashes from fallback to web font
fa-brands-400.woff2woff2swap
Size115 KB
Load time34 ms
Start855 ms
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
slick.woffwoffswap
Size1 KB
Load time14 ms
Start971 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
fa-solid-900.woff2woff2swap
Size73 KB
Load time12 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
Optimization checklist
Preload critical fonts (priority=high)
Use woff2 format for all fonts
Set font-display to swap, optional, or fallback
Subset large fonts (≤100 KB each)
Fixing the unchecked items could save ~135 KB and ~270 ms
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
✓
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
80 requests over 2356ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100%of JavaScript execution is third-party
First-party Third-party4269ms · 1163KB · $57/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Unattributable
Unattributable
Other
931ms
0 KB
—
$12/mo
Costly
www.transportation.gov
www.transportation.gov
Other
672ms
9 KB
—
$9/mo
Costly
www.transportation.gov
www.transportation.gov
Other
560ms
84 KB
58%
$7/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
310ms
156 KB
42%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
284ms
156 KB
41%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
279ms
153 KB
42%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
269ms
147 KB
43%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
229ms
117 KB
53%
$3/mo
Costly
www.transportation.gov
www.transportation.gov
Other
180ms
17 KB
—
$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
166ms
116 KB
55%
$2/mo
Optional
dap.digitalgov.gov
dap.digitalgov.gov
Other
112ms
5 KB
—
$1/mo
Optional
gov1.siteintercept.qualtrics.com
gov1.siteintercept.qualtrics.com
Other
98ms
36 KB
70%
$1/mo
Optional
Google Analytics
www.google-analytics.com
Analytics
91ms
21 KB
—
$1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
89ms
147 KB
72%
$1/mo
Optional
Unattributable
Other
Costly
Execution931ms
Transfer0 KB
Monthly Cost$12/mo
www.transportation.gov
Other
Costly
Execution672ms
Transfer9 KB
Monthly Cost$9/mo
www.transportation.gov
Other
Costly
Execution560ms
Transfer84 KB
Unused58%
Monthly Cost$7/mo
Google Tag Manager
Tag Manager
Costly
Execution310ms
Transfer156 KB
Unused42%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution284ms
Transfer156 KB
Unused41%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution279ms
Transfer153 KB
Unused42%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution269ms
Transfer147 KB
Unused43%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution229ms
Transfer117 KB
Unused53%
Monthly Cost$3/mo
www.transportation.gov
Other
Optional
Execution180ms
Transfer17 KB
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Optional
Execution166ms
Transfer116 KB
Unused55%
Monthly Cost$2/mo
dap.digitalgov.gov
Other
Optional
Execution112ms
Transfer5 KB
Monthly Cost$1/mo
gov1.siteintercept.qualtrics.com
Other
Optional
Execution98ms
Transfer36 KB
Unused70%
Monthly Cost$1/mo
Google Analytics
Analytics
Optional
Execution91ms
Transfer21 KB
Monthly Cost$1/mo
Google Tag Manager
Tag Manager
Optional
Execution89ms
Transfer147 KB
Unused72%
Monthly Cost$1/mo
These scripts may cost more than they're worth
Unattributable adds 931ms and costs ~$12/month
www.transportation.gov adds 672ms and costs ~$9/month
www.transportation.gov adds 560ms and costs ~$7/month
Google Tag Manager adds 310ms and costs ~$4/month
Google Tag Manager adds 284ms and costs ~$4/month
Google Tag Manager adds 279ms and costs ~$4/month
Google Tag Manager adds 269ms and costs ~$4/month
Google Tag Manager adds 229ms and costs ~$3/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
Unattributable takes 931ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.transportation.gov takes 672ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.transportation.gov takes 560ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
58% of www.transportation.gov's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Google Tag Manager takes 310ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 284ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 279ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 269ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 229ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
53% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
55% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
70% of gov1.siteintercept.qualtrics.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
72% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.